Physics Quiz

A mass m attached to a horizontal massless spring with spring constant k, is set into simple harmonic motion. Its maximum displacement from its equilibrium position is A. What is the masses speed as it passes through its equilibrium position?

• 0

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A force F at an angle θ above the horizontal is used to pull a heavy suitcase of weight mg a distance d along a level floor at constant velocity. The coefficient of friction between the floor and the suitcase is μ. The work done by the frictional force is:

• -Fd cos θ

• -μ Fd cos θ

• -μmgd

• -μ mgd cos θ

A 2 kg ball is attached to a 0.80 m string and whirled in a horizontal circle at a constant speed of 6 m/s. The work done on the ball during each revolution is:

• 90 J

• 72 J

• 16 J

• zero

A pendulum bob of mass m on a cord of length L is pulled sideways until the cord makes an angle θ with the vertical as shown in the figure to the right. The change in potential energy of the bob during the displacement is:

• mgL (1-cos θ)

• mgL (1-sin θ)

• mgL sin θ

• mgL cos θ

A softball player catches a ball of mass m, which is moving towards her with horizontal speed V. While bringing the ball to rest, her hand moved back a distance d. Assuming constant deceleration, the horizontal force exerted on the ball by the hand is

• mV²/(2d)

• mV²/d

• 2mV/d

• mV/d

A pendulum is pulled to one side and released. It swings freely to the opposite side and stops. Which of the following might best represent graphs of kinetic energy (Eₖ), potential energy (Eₚ) and total mechanical energy (Eₜ)?

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A car of mass m slides across a patch of ice at a speed v with its brakes locked. It then hits dry pavement and skids to a stop in a distance d. The coefficient of kinetic friction between the tires and the dry road is μ. If the car has a mass of 2m, it would have skidded a distance of

• 0.5 d

• d

• 1.41 d

• 2 d

A car of mass m slides across a patch of ice at a speed v with its brakes locked. It then hits dry pavement and skids to a stop in a distance d. The coefficient of kinetic friction between the tires and the dry road is μ. If the car has a speed of 2v, it would have skidded a distance of

• d

• 1.41 d

• 2 d

• 4 d

A ball is thrown vertically upwards with a velocity v and an initial kinetic energy Eₖ. When half way to the top of its flight, it has a velocity and kinetic energy respectively of

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A football is kicked off the ground a distance of 50 yards downfield. Neglecting air resistance, which of the following statements would be INCORRECT when the football reaches the highest point?

• all of the ball's original kinetic energy has been changed into potential energy

• the ball's horizontal velocity is the same as when it left the kicker's foot

• the ball will have been in the air one-half of its total flight time

• the vertical component of the velocity is equal to zero