91Ó°ÊÓ

Consult your online resources for additional practice. A man walks \(30 \mathrm{m}\) east and then \(40 \mathrm{m}\) north. What is the difference between his traveled distance and his displacement? (A) 0 m (B) 20 m (C) 50 m (D) 70 m

A 1000 kg rocket ship, travelling at \(100 \frac{\mathrm{m}}{\mathrm{s}},\) is acted upon by an average force of \(20 \mathrm{kN}\) applied in the direction of its motion for \(8 \mathrm{s}\) What is the change in velocity of the rocket? A. \(160 \frac{\mathrm{m}}{\mathrm{s}}\) B. \(160 \frac{\mathrm{m}}{\mathrm{s}}\) C. \(160,000 \frac{\mathrm{m}}{\mathrm{s}}\) \(160,000 \frac{\mathrm{m}}{\mathrm{s}}\)

A car is traveling at \(40 \frac{\mathrm{km}}{\mathrm{hr}}\) and the driver puts on the brakes, bringing the car to rest in a time of 6 s. What is the magnitude of the average acceleration of the car? A. \(240 \frac{\mathrm{km}}{\mathrm{hr}^{2}}\) B. \(12,000 \frac{\mathrm{km}}{\mathrm{hr}^{2}}\) C. \(12,000 \frac{\mathrm{km}}{\mathrm{hr}^{2}}\) D. \(12,000 \frac{\mathrm{km}}{\mathrm{hr}^{2}}\)

A \(10 \mathrm{kg}\) wagon rests on a frictionless inclined plane. The plane makes an angle of \(30^{\circ}\) with the horizontal. Approximately how large is the force required to keep the wagon from sliding down the plane (Note: \(\left.\sin 30^{\circ}=0.5, \cos 30^{\circ}=0.866\right) ?\) A \(10 \mathrm{N}\) B \(49 \mathrm{N}\) C \(85 \mathrm{N}\) D \(98 \mathrm{N}\)

A \(30 \mathrm{kg}\) girl sits on a seesaw at a distance of \(2 \mathrm{m}\) from the fulcrum. Where must her father sit to balance the seesaw if he has a mass of \(90 \mathrm{kg} ?\) (A) 67 cm from the girl (B) 67 cm from the fulcrum (C) 133 cm from the girl (D) 267 cm from the fulcrum

A rock \((m=2 \mathrm{kg})\) is shot up vertically at the same time that a ball \((\mathrm{m}\) \(=0.5 \mathrm{kg}\) ) is projected horizontally. If both start from the same height: (A) the rock and ball will reach the ground at the same time. (B) the rock will reach the ground first. (C) the ball will reach the ground first. (D) the rock and ball will collide in the air before reaching the ground.

Centrifugal force is an apparent outward force during circular motion. It has been described as a reaction force according to Newton's third law. Which of the following statements is most likely to be correct regarding centrifugal force? A. Centrifugal force exists only for uniform circular motion, not nonuniform circular motion. B. Centrifugal force exists only when tension or a normal force provides centripetal acceleration. C. Centrifugal force always acts antiparallel to the centripetal force vector. D. Centrifugal force is result of repulsive electrostatic interactions.

Which of the following statements is true of movement on a plane with friction? Acceleration is a function of applied force only. More force is needed to accelerate a stationary object than an identical moving object. The force of friction is independent of the mass of objects. (A) I only (B) II only (C) I and II only (D) I and III only