Projectile Motion - Questions

Projectile Motion
































































A bomber is approaching its target in straight and level flight. The altitude of the bomber is such that a bomb will take two minutes to fall. The bombardier should release the bombs

(A) at the instant that the plane is passing over the target.
(B) one minute before the plane passes over the target.
(C) two minutes before the plane passes over the target.
(D) three minutes before the plane passes over the target.
(E) four minutes before the plane passes over the target.


Questions --- What this question is about
13.1































































A bomber is approaching its target in straight and level flight. The altitude of the bomber is such that a bomb will take two minutes to fall. The bombardier should release the bombs

(A) at the instant that the plane is passing over the target.

No. The bomb keeps moving horizontally with the plane and over-shoots the target.

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Questions --- What this question is about
13.1































































A bomber is approaching its target in straight and level flight. The altitude of the bomber is such that a bomb will take two minutes to fall. The bombardier should release the bombs

(B) one minute before the plane passes over the target.

No. The bomb will still be under the plane for one minute after the target is passed.

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13.1












































































































A bomber is approaching its target in straight and level flight. The altitude of the bomber is such that a bomb will take two minutes to fall. The bombardier should release the bombs

(C) two minutes before the plane passes over the target.

Yes. The bomb will stay under the plane until it hits.

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13.1































































A bomber is approaching its target in straight and level flight. The altitude of the bomber is such that a bomb will take two minutes to fall. The bombardier should release the bombs

(D) three minutes before the plane passes over the target.

No. The bomb will hit one minute before the target is reached.

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Questions --- What this question is about
13.1































































A bomber is approaching its target in straight and level flight. The altitude of the bomber is such that a bomb will take two minutes to fall. The bombardier should release the bombs

(E) four minutes before the plane passes over the target.

No. The bomb will hit two minutes before it reaches the target.

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13.1

































































It is the year 2060 and you are participating in the 30th annual lunar skeet shoot. As a clay pigeon comes flying up from behind one of the moon's craters, you trigger your computerized magnetic rifle and let fly with an iron slug. Since there is no air on the moon, you can count on the uncomplicated laws of projectile motion that you learned in physics class. Your rifle is aimed by a computer which is designed to operate in open space where there is no gravity to contend with. Thus it aims at a point ahead of the pigeon where a straight-line path would predict it to be when the slug arrives. The computer does not take the moon's gravity into account and does not know that the pigeon is actually following a curved trajectory.

(A) you hit the pigeon anyway.
(B) your slug always flies above the pigeon.
(C) your slug always flies below the pigeon.


Questions --- What this question is about
13.2

































































It is the year 2060 and you are participating in the 30th annual lunar skeet shoot. As a clay pigeon comes flying up from behind one of the moon's craters, you trigger your computerized magnetic rifle and let fly with an iron slug. Since there is no air on the moon, you can count on the uncomplicated laws of projectile motion that you learned in physics class. Your rifle is aimed by a computer which is designed to operate in open space where there is no gravity to contend with. Thus it aims at a point ahead of the pigeon where a straight-line path would predict it to be when the slug arrives. The computer does not take the moon's gravity into account and does not know that the pigeon is actually following a curved trajectory.

(A) you hit the pigeon anyway.

Yes. Both the slug and the pigeon fall below their no-gravity positions in the same way.

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Questions --- What this question is about
13.2

































































It is the year 2060 and you are participating in the 30th annual lunar skeet shoot. As a clay pigeon comes flying up from behind one of the moon's craters, you trigger your computerized magnetic rifle and let fly with an iron slug. Since there is no air on the moon, you can count on the uncomplicated laws of projectile motion that you learned in physics class. Your rifle is aimed by a computer which is designed to operate in open space where there is no gravity to contend with. Thus it aims at a point ahead of the pigeon where a straight-line path would predict it to be when the slug arrives. The computer does not take the moon's gravity into account and does not know that the pigeon is actually following a curved trajectory.

(B) your slug always flies above the pigeon.

No. The slug is falling too.

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Questions --- What this question is about
13.2

































































It is the year 2060 and you are participating in the 30th annual lunar skeet shoot. As a clay pigeon comes flying up from behind one of the moon's craters, you trigger your computerized magnetic rifle and let fly with an iron slug. Since there is no air on the moon, you can count on the uncomplicated laws of projectile motion that you learned in physics class. Your rifle is aimed by a computer which is designed to operate in open space where there is no gravity to contend with. Thus it aims at a point ahead of the pigeon where a straight-line path would predict it to be when the slug arrives. The computer does not take the moon's gravity into account and does not know that the pigeon is actually following a curved trajectory.

(C) your slug always flies below the pigeon.

No. The pigeon is falling too.

Try again.
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Fred, the intrepid motorcycle maniac, wants to jump his motorcycle across the largest possible distance. To the extent that he can ignore air resistance, the best angle for his take-off ramp is

(A) thirty degrees from the horizontal.
(B) 53.7 degrees from the horizontal.
(C) forty-five degrees from the horizontal.

Questions --- What this question is about
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Fred, the intrepid motorcycle maniac, wants to jump his motorcycle across the largest possible distance. To the extent that he can ignore air resistance, the best angle for his take-off ramp is

(A) thirty degrees from the horizontal.
No. He can do better.

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13.3

































































Fred, the intrepid motorcycle maniac, wants to jump his motorcycle across the largest possible distance. To the extent that he can ignore air resistance, the best angle for his take-off ramp is

(B) 53.7 degrees from the horizontal.
No. He would sort of pop up and land short.

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13.3

































































Fred, the intrepid motorcycle maniac, wants to jump his motorcycle across the largest possible distance. To the extent that he can ignore air resistance, the best angle for his take-off ramp is

(C) forty-five degrees from the horizontal.
Yes.

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13.3

































































A cannon shoots a shell up with an initial vertical velocity component of 500 m/s and an initial horizontal component of 400 m/s. Neglecting air resistance and the curvature of the Earth, how far away from the cannon will the shell hit?

(A) 50,000 m. (B) 20,000 m. (C) 40,000 m.


Questions --- What this question is about
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A cannon shoots a shell up with an initial vertical velocity component of 500 m/s and an initial horizontal component of 400 m/s. Neglecting air resistance and the curvature of the Earth, how far away from the cannon will the shell hit?

(A) 50,000 m. --- No.
Figure out how long it is in the air.

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Questions --- What this question is about
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A cannon shoots a shell up with an initial vertical velocity component of 500 m/s and an initial horizontal component of 400 m/s. Neglecting air resistance and the curvature of the Earth, how far away from the cannon will the shell hit?
(B) 20,000 m. --- No.
The time in the air is twice the time
it takes to reach maximum altitude.

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Questions --- What this question is about
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A cannon shoots a shell up with an initial vertical velocity component of 500 m/s and an initial horizontal component of 400 m/s. Neglecting air resistance and the curvature of the Earth, how far away from the cannon will the shell hit?
(C) 40,000 m. --- Yes.
Multiply time in the air by 400 m/s:
(100 s)(400 m/s) = 40,000 m..

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Suppose that there is a cannon which can fire shells at any speed. If this cannon is located on the earth's surface, its shells

(A) could go into earth orbit if fired at a high enough speed.
(B) could never go into earth orbit.
(C) always return to the earth.



Questions --- What this question is about
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Suppose that there is a cannon which can fire shells at any speed. If this cannon is located on the earth's surface, its shells

(A) could go into earth orbit if fired at a high enough speed.

No. At best, they could return to the firing point.

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Suppose that there is a cannon which can fire shells at any speed. If this cannon is located on the earth's surface, its shells

(B) could never go into earth orbit.
Correct. They need to be launched from "Newton's Mountain".

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13.5































































Suppose that there is a cannon which can fire shells at any speed. If this cannon is located on the earth's surface, its shells

(C) always return to the earth.

No. Given escape velocity, they will never come back.

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Questions --- What this question is about
13.5