OCR A Level Physics

Topic Questions

3.8 Newton's Laws of Motion & Momentum

1
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1 mark

Below is a diagram of two identical particles, X and Y which have masses mX and mY respectively. Particle X collides into Particle Y with a velocity of v0 and they move off in different directions. Particle X moves off with a velocity of v1  at an angle of θ1 to the original direction of motion. Particle Y moves off with a velocity of v2 at angle θ2.

3-8-mcq-h-q1-ocr-al-physics

Which one of the following equations is correct?

  • mXv1cosθ1 = mYv2cosθ2

  • fraction numerator m subscript X v subscript 1 over denominator m subscript Y v subscript 2 end fraction equals fraction numerator sin theta subscript 2 over denominator sin theta subscript 1 end fraction

  • mXv0 = mXv1sinθ1mYv2sinθ2 

  • (mX + mY)v0 = mXv1cosθ1 + mYv2cosθ2

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2
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1 mark

Snooker ball P traveling at speed 3v hits an identical Snooker ball Q which is moving in the opposite direction at speed v. After the collision Snooker ball P has speed v over 2 and Snooker ball Q has speed x and move off in the direction Snooker ball P was originally traveling in.

Which statement is true?

  • The collision is elastic

  • Speed x is equal to 3 over 2v

  • The initial kinetic energy is begin inline style 5 over 2 end stylemv2

  • None of the statements are true

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3
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1 mark

A particle increases in acceleration at a constant rate for 3 s. It then has constant acceleration for a further 4.5 s. The total impulse of the object is 54 N s. 

Which graph correctly describes the force of the particle?

  • 3-8-mcq-h-q3a-ocr-al-physics

  • 3-8-mcq-h-q3b-ocr-al-physics

  • 3-8-mcq-h-q3c-ocr-al-physics

  • 3-8-mcq-h-q3d-ocr-al-physics

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1
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1 mark

A puck of mass 0.16 kg is sliding on ice with a constant velocity of 11.0 m s−1. A hockey stick exerts a force on the puck, for a short period of time, in the opposite direction to the velocity of the puck.
The momentum of the puck changes by 2.0 kg m s−1.

Ignore friction.

What is the speed of the puck when it leaves the hockey stick?

  • 1.5 m s−1

  • 3.8 m s−1

  • 12.5 m s−1

  • 23.5 m s−1

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2
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1 mark

An electron moves in a circle of radius 2.0 cm in a uniform magnetic field of flux density 170 mT.

What is the momentum of this electron?

  • 3.4 × 10−3 kg m s−1

  • 5.4 × 10−17 kg m s−1

  • 1.4 × 10−18 kg m s−1

  • 5.4 × 10−22 kg m s−1

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3
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1 mark

A person of mass 80 kg is standing in a lift which is initially at rest. The lift accelerates upwards at 2.0 ms-2 for 1 s and then continues to move upwards with a constant velocity for 3 s.

Which graph shows how the reaction force, R, from the floor of the lift on the person varies during this motion?

3-8-mcq-m-q1-ocr-al-physics

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4
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1 mark

A trolley P of mass 5 kg travelling at 2 ms-1 collides head-on with a trolley Q of mass 3 kg traveling at a speed v.

The impulse applied to trolley P in the collision is 6.3 N s.

As a result of the collision, trolley Q’s direction is reversed and its speed is halved.

Find v.

  • 0.7 ms-1

  • 1.4 ms-1

  • 1.5 ms-1

  • 4.2 ms-1

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