Physics Test 1 (CH1-4)

A boat, whose speed in still water is 1.75 m/s, must aim upstream at an angle of 26.3e (with respect to a line perpendicular to the shore) in order to travel directly across the stream. (a) Determine the speed of the current. (b) Determine the resultant speed of the boat with respect to the shore.

(a) 0.775 m/s (b) 1.57 m/s

A projectile is shot horizontally at 23.4 m/s from the roof of a building 55.0 m tall. (a) Determine the time necessary for the projectile to reach the ground below. (b) Determine the distance from the base of the building that the projectile lands. (c) Determine the horizontal and vertical components of the velocity just before the projectile reaches the ground.

(a) 3.35 s (b) 78.4 m (c) vhorizontal = 23.4 m/s, vvertical = 32.8 m/s

A projectile is fired from ground level with an initial speed of 55.6 m/s at an angle of 41.2e above the horizontal. (a) Determine the time necessary for the projectile to reach its maximum height. (b) Determine the maximum height reached by the projectile. (c) Determine the horizontal and vertical components of the velocity vector at the maximum height. (d) Determine the horizontal and vertical components of the acceleration vector at the maximum height.

(a) 3.73 s (b) 68.3 m (c) vhorizontal = 41.8 m/s, vvertical = 0 (d) ahorizontal = 0, avertical = -9.8 m/s2

Vector A is 5.5 cm long and points along the x axis. Vector B is 7.5 cm long and points at +30e to the negative x axis. (a) Determine the x and y components of Vector A . (b) Determine the x and y components of Vector B. (c) Determine the sum of these two vectors in terms of components. (d) Determine the sum of these two vectors in terms of magnitude and direction.

(a) Ax = 5.5 cm, Ay = 0 (b) Bx = -6.5 cm, By = 3.8 cm (c) Rx = -1.0 cm, Ry = 3.8 cm (d) 3.9 cm at 75e above -x axis

Vector A is 75.0 cm long and points at 30e above the positive x axis. Vector B is 25.0 cm long and points along the negative x axis. Vector C is 40.0 cm long and points at 45e below the negative x axis. (a) Determine the x and y components of Vector A . (b) Determine the x and y components of Vector B . (c) Determine the x and y components of Vector C . (d) Determine the sum of these three vectors in terms of components. (e) Determine the sum of these three vectors in terms of magnitude and direction.

(a) Ax = 65 cm, Ay = 38 cm (b) Bx = -25 cm, By = 0 (c) Cx = 21 cm, Cy = -21 cm (d) Rx = 61 cm, Ry = 17 cm (e) 63 cm at 20e above x axis

Two boxes are connected by a cord running over a pulley as shown in Fig. 4-5. Box I of mass 8.0 kg rest on the top of the table; the coefficient of kinetic friction between box I and the table is 0.10. Box II has a mass of 15.0 kg. (a) Draw the free-body diagrams for the two boxes, identifying all of the forces acting on each of the masses. (b) Calculate the acceleration of the system. (c) Calculate the tension in the cord.

(a) Box one is acted on by the force of gravity in a downward direction, the normal force due to the table top in an upward direction, the tension in the string toward the right, and the force of friction due to the table top toward the left. Box two is acted on by the force of gravity in a downward direction and the tension in the string in an upward direction. (b) 6.1 m/s2 (c) 56 N

A block lies on a smooth inclined plane tilted at an angle of 35e to the horizontal. (a) Draw the free-body diagram for the block. (b) Determine the block's acceleration as it slides down the inclined plane. (c) If the block started from rest 8.5 m up the incline from its base, determine the block's speed when it reaches the bottom of the incline. (d) How long did it take the block to reach the bottom of the inclined plane?

(a) The block is acted on by the force of gravity directed downward and the normal force due to the inclined plane directed perpendicular to the inclined surface. (b) 5.6 m/s2 (c) 9.7 m/s (d) 1.7 s

A 25.0-kg box is released from rest on a rough inclined plane tilted at an angle of 33.5e to the horizontal. The coefficient of kinetic friction between the box and the inclined plane is 0.200. (a) Draw the free-body diagram for the box. (b) Determine the force of kinetic friction acting on the box. (c) Determine the acceleration of the box as it slides down the inclined plane.

(a) The box is acted on by the force of gravity directed downward, the normal force due to the inclined plane directed perpendicular to the surface of the incline, and the force of friction due to the inclined plane directed parallel to the inclined surface in the direction opposite of the motion. (b) 40.9 N (c) 3.77 m/s2

At the instant a traffic light turns green, a car that has been waiting at the intersection starts ahead with a constant acceleration of 2.00 m/s2. At that moment a truck traveling with a constant velocity of 15.0 m/s overtakes and passes the car.

(a.) 15.0 s (b.) 225 m (c.) 30.0 m/s

A foul ball is hit straight up into the air with a speed of 30.0 m/s. (a.) Calculate the time required for the ball to rise to its maximum height. (b.) Calculate the maximum height reached by the ball. (c.) Determine the time at which the ball pass a point 25.0 m above the point of contact between the bat and ball. (d.) Explain why there are two answers to part c.

(a.) 3.06 s (b.) 45.9 m (c.) 0.995 s and 5.13 s (d.) One value for the ball traveling upward; one value for the ball traveling downward.

A ball is thrown straight up with a speed of 30 m/s. (a.) How long does it take the ball to reach the maximum height? (b.) What is the maximum height reached by the ball? (c.) What is its speed after 4.2 s?

(a.) 3.1 s (b.) 46 m (c.) 11 m/s

A car with good tires on a dry road can decelerate at about 5.0 m/s2 when braking. Suppose a car is initially traveling at 55 mi/h. (a.) How much time does it take the car to stop? (b.) What is the stopping distance?

(a.) 4.9 s (b.) 60 m

55 mi/h is how many m/s? (1 mi = 1609 m.) A) 25 m/s B) 49 m/s C) 90 m/s D) 120 m/s

A

A 10-kg box sitting on a horizontal surface is pulled by a 5.0-N force. A 3.0-N friction force retards the motion. What is the acceleration of the object? A) 0.20 m/s2 B) 0.30 m/s2 C) 0.50 m/s2 D) 5.0 m/s2

A

A 400-m tall tower casts a 600-m long shadow over a level ground. At what angle is the Sun elevated above the horizon? A) 34e B) 42e C) 48e D) can't be found; not enough information

A

A bulldozer drags a log weighing 500 N along a rough surface. The cable attached to the log makes an angle of 30.0e with the ground. The coefficient of static friction between the log and the ground is 0.500. What minimum tension is required in the cable in order for the log to begin to move? A) 224 N B) 268 N C) 289 N D) 500 N

A

A bullet moving horizontally to the right (+x direction) with a speed of 500 m/s strikes a sandbag and penetrates a distance of 10.0 cm. What is the average acceleration, in m/s2, of the bullet? A) -1.25 ˛ 106 B) -2.50 ˛ 106 C) -1.25 ˛ 103 D) -2.50 ˛ 103

A

A car decelerates uniformly and comes to a stop after 10 s. The car's average velocity during deceleration was 50 km/h. What was the car's deceleration while slowing down? A) 10 km/h-s B) 8.0 km/h-s C) 5.0 km/h-s D) 4.0 km/h-s

A

A fighter plane moving 200 m/s horizontally fires a projectile with speed 50.0 m/s in a forward direction 30.0e below the horizontal. What is the speed of the projectile with respect to a stationary observer on the ground? A) 245 m/s B) 250 m/s C) 268 m/s D) 293 m/s

A

A mass is placed on a smooth inclined plane with an angle of 37e to the horizontal. If the inclined plane is 5.0-m long, how long does it take for the mass to reach the bottom of the inclined plane after it is released from rest? A) 1.3 s B) 1.2 s C) 1.1 s D) 1.0 s

A

A plane is flying due South (270e) at 500 km/h. A wind blows from East to West (180e) at 45.0 km/h. Find the plane's velocity with respect to the ground. A) 502 km/h at 265e B) 502 km/h at 85e C) 520 km/h at 5e D) 545 km/h at 265e

A

A polar bear starts at the North Pole. It travels 1.0 km south, then 1.0 km east, then 1.0 km north, then 1.0 km west to return to its starting point. This trip takes 45 min. What was the bear's average velocity? A) 0 km/h B) 0.09 km/h C) 4.5 km/h D) 5.3 km/h

A

A swimmer heading directly across a river 200 m wide reaches the opposite bank in 6 min 40 s. She is swept downstream 480 m. How fast can she swim in still water? A) 0.50 m/s B) 1.2 m/s C) 1.4 m/s D) 1.8 m/s

A

A wooden block slides directly down an inclined plane, at a constant velocity of 6.0 m/s. What is the coefficient of kinetic friction, if the plane makes an angle of 25e with the horizontal? A) 0.47 B) 0.42 C) 0.37 D) 0.91

A

An antitank weapon fires a 3.00-kg rocket which acquires a speed of 50.0 m/s after traveling 90.0 cm down a launching tube. Assuming the rocket was accelerated uniformly, what is the average force acted on it? A) 4.17 ˛ 103 N B) 3.62 ˛ 103 N C) 2.82 ˛ 103 N D) 2.00 ˛ 103 N

A

An object is on a frictionless inclined plane. The plane is inclined at an angle of 30e with the horizontal. What is the object's acceleration? A) 0.50 g B) 0.56 g C) 0.87 g D) 1.0 g

A

An object is thrown upward with a speed of 12 m/s on the surface of planet X where the acceleration due to gravity is 1.5 m/s2. How long does it take for the object to reach the maximum height? A) 8.0 s B) 11 s C) 14 s D) 16 s

A

An object slides on a level surface in the +x direction. It slows and comes to a stop with a constant acceleration of -2.45 m/s2. What is the coefficient of kinetic friction between the object and the floor? A) 0.25 B) 0.50 C) 4.9 D) Impossible to determine without knowing the mass of the object.

A

An object with a mass m slides down a rough 37e inclined plane where the coefficient of kinetic friction is 0.20. What is the acceleration of the object? A) 4.3 m/s2 B) 5.9 m/s2 C) 6.6 m/s2 D) 7.8 m/s2

A

If you walk 6.0 km in a straight line in a direction north of east and you end up 2.0 km north and several kilometers east. How many degrees north of east have you walked? A) 19e B) 45e C) 60e D) 71e

A

In Fig. 2-1, what is the average velocity from 0 to 6.0 s? A) 0 B) 10 m/s C) 20 m/s D) -40 m/s

A

In Fig. 2-1, what is the velocity at t = 4.0 s? A) 0 B) 10 m/s C) 20 m/s D) -40 m/s

A

In Fig. 2-2, what is the acceleration at 3.0 s? A) 0 B) 2.0 m/s2 C) -2.5 m/s2 D) 10 m/s2

A

The coefficient of static and kinetic frictions between a 3.0-kg box and a desk are 0.40 and 0.30, respectively. What is the net force on the box when a 15 N horizontal force is applied to the box? A) 6.2 N B) 12 N C) 8.8 N D) zero

A

Three vectors, expressed in Cartesian coordinates, are x comp y comp S -3.5 +4.5 T 0 -6.5 U +5.5 -2.5 What is the magnitude of the resultant vector S + T + U ? A) 4.9 B) 24 C) 16 D) 18

A

Two boxes of masses m and 2m are connected by a rope. (See Fig. 4-4.) If the forward force on the more massive box is F, what is the acceleration of the less massive box? A) F/(3m) B) F/(2m) C) F/m D) 2F/m

A

Two boxes of masses m and 2m are in contact with each other on a frictionless surface. (See Fig. 4-3.) What is the net force on the more massive box? A) 2/3 F B) F C) 3/2 F D) 2F

A

What is the mass of a person who weighs 110 lb? A) 50 kg B) 55 kg C) 110 kg D) 242 kg

A

A horizontal force of 5.0 N accelerates a 4.0-kg mass, from rest, at a rate of 0.50 m/s2 in the positive direction. What friction force acts on the mass? A) 2.0 N B) 3.0 N C) 4.0 N D) 5.0 N

B

A 10-kg mass slides down a flat hill that makes an angle of 10e with the horizontal. If friction is negligible, what is the resultant force on the sled? A) 1.7 N B) 17 N C) 97 N D) 98 N

B

A ball is thrown straight up with a speed of 36.0 m/s. How long does it take to return to its starting point? A) 3.67 s B) 7.35 s C) 11.0 s D) 14.7 s

B

A ball is thrown upward at a velocity of 19.6 m/s. What is its velocity after 3.00 s? A) 9.8 m/s upward B) 9.8 m/s downward C) zero D) 19.6 downward

B

A motorist travels 160 km at 80 km/h and 160 km at 100 km/h. What is the average speed of the motorist for this trip? A) 84 km/h B) 89 km/h C) 90 km/h D) 91 km/h

B

A motorist travels for 3.0 h at 80 km/h and 2.0 h at 100 km/h. What is her average speed for the trip? A) 85 km/h B) 88 km/h C) 90 km/h D) 92 km/h

B

A person of weight 480 N stands on a scale in an elevator. What will the scale be reading when the elevator is accelerating downward at 4.00 m/s2? A) 196 N B) 284 N C) 676 N D) 480 N

B

A person on a scale rides in an elevator. If the mass of the person is 60.0 kg and the elevator accelerates downward with an acceleration of 4.90 m/s2, what is the reading on the scale? A) 147 N B) 294 N C) 588 N D) 882 N

B

A projectile is launched with an initial velocity of 60.0 m/s at an angle of 30.0e above the horizontal. What is the maximum height reached by the projectile? A) 23 m B) 46 m C) 69 m D) 92 m

B

A rifle bullet is fired at an angle of 30e below the horizontal with an initial velocity of 800 m/s from the top of a cliff 80 m high. How far from the base of the cliff does it strike the level ground below? A) 130 m B) 140 m C) 150 m D) 160 m

B

A sports car of mass 1000 kg can accelerate from rest to 27 m/s in 7.0 s. What is the average forward force on the car? A) 2.6 ˛ 102 N B) 3.9 ˛ 103 N C) 2.7 ˛ 104 N D) 1.9 ˛ 105 N

B

A stack of books rests on a level frictionless surface. A force F acts on the stack, and it accelerates at 3.0 m/s2. A 1.0 kg book is then added to the stack. The same force is applied, and now the stack accelerates at 2.0 m/s2. What was the mass of the original stack? A) 1.0 kg B) 2.0 kg C) 3.0 kg D) none of the above

B

A swimmer heading directly across a river 200 m wide reaches the opposite bank in 6 min 40 s. She is swept downstream 480 m. What is the speed of the current? A) 0.50 m/s B) 1.2 m/s C) 1.4 m/s D) 1.8 m/s

B

An airplane travels at 300 mi/h south for 2.00 h and then at 250 mi/h north for 750 miles. What is the average speed for the trip? A) 260 mi/h B) 270 mi/h C) 275 mi/h D) 280 mi/h

B

An airplane with a speed of 120 km/h is headed 30.0e east of north in a wind blowing due west at 30.0 km/h. What is the speed of the plane relative to the ground? A) 90.0 km/h B) 110 km/h C) 137 km/h D) 150 km/h

B

An object is moving in a straight line with constant acceleration. Initially it is traveling at 16 m/s. Three seconds later it is traveling at 10 m/s. How far does it move during this time? A) 30 m B) 39 m C) 48 m D) 57 m

B

An object is thrown upward with a speed of 14 m/s on the surface of planet X where the acceleration due to gravity is 3.5 m/s2. What is the speed of the object after 8.0 s? A) 7.0 m/s B) 14 m/s C) 21 m/s D) 64 m/s

B

An object moves 15.0 m north and then 11.0 m south. Find both the distance traveled and the magnitude of the displacement vector. A) 4.0 m, 26.0 m B) 26.0 m, 4.0 m C) 26.0 m, 26.0 m D) 4.0 m, 4.0 m

B

An object of mass 6000 kg rests on the flatbed of a truck. It is held in place by metal brackets that can exert a maximum horizontal force of 9000 N. When the truck is traveling 15 m/s, what is the minimum stopping time if the load is not to slide forward into the cab? A) 5.0 s B) 10 s C) 13 s D) 23 s

B

An object sits on a frictionless surface. A 16-N force is applied to the object, and it accelerates at 2.0 m/s2. What is the mass of the object? A) 4.0 kg B) 8.0 kg C) 32 kg D) 78 N

B

During a hockey game, a puck is given an initial speed of 10 m/s. It slides 50 m on the ice before it stops. What is the coefficient of kinetic friction between the puck and the ice? A) 0.090 B) 0.10 C) 0.11 D) 0.12

B

Human reaction time is usually greater than 0.10 s. If your friend holds a ruler between your fingers and releases it without warning, how far can you expect the ruler to fall before you catch it? A) at least 3.0 cm B) at least 4.9 cm C) at least 6.8 cm D) at least 9.8 cm

B

If a ball is thrown with a velocity of 25 m/s at an angle of 37e above the horizontal, what is the vertical component of the velocity? A) 12 m/s B) 15 m/s C) 19 m/s D) 25 m/s

B

If you push a 4.0-kg mass with the same force that you push a 10-kg mass from rest, A) the 10-kg mass accelerates 2.5 times faster than the 4.0-kg mass. B) the 4.0-kg mass accelerates 2.5 times faster than the 10-kg mass. C) both masses accelerate at the same rate. D) None of the above is true.

B

In Fig. 2-1, what is the average velocity from 0 to 4.0 s? A) 0 B) 10 m/s C) 20 m/s D) -40 m/s

B

In Fig. 2-1, what is the velocity at t = 1.0 s? A) 0 B) 10 m/s C) 20 m/s D) -40 m/s

B

In Fig. 2-2, what is the average acceleration from 0 to 5.0 s? A) 0 B) 2.0 m/s2 C) -2.5 m/s2 D) 10 m/s2

B

In a 400-m relay race the anchorman (the person who runs the last 100 m) for team A can run 100 m in 9.8 s. His rival, the anchorman for team B, can cover 100 m in 10.1 s. What is the largest lead the team B runner can have when the team A runner starts the final leg of the race, in order that the team A runner not lose the race? A) 2.0 m B) 3.0 m C) 4.0 m D) 5.0 m

B

In the Atwood machine shown in Fig. 4-1, if M = 0.60 kg and m = 0.40 kg, what is the tension in the string? (Ignore friction and the mass of the pulley.) A) 3.1 N B) 4.7 N C) 7.1 N D) 7.5 N

B

Object A weighs 40 N on Earth, and object B weighs 40 N on the Moon. The Moon's gravity is one sixth of Earth's. Compare the masses of the objects. A) A has 6 times the mass of B. B) B has 6 times the mass of A. C) A and B have equal mass. D) The situation as stated is impossible.

B

On a calm day (no wind), you can run a 1500-m race at a velocity of 4.0 m/s. If you ran the same race on a day when you had a constant headwind which slows your speed by 2.0 m/s, the time it would take you to finish would be A) 250 s. B) 750 s. C) 1125 s. D) 9000 s.

B

Sue and Sean are having a tug-of-war by pulling on opposite ends of a 5.0-kg rope. Sue pulls with a 15-N force. What is Sean's force if the rope accelerates toward Sue at 2.0 m/s2? A) 3.0 N B) 5.0 N C) 25 N D) 50 N

B

The driver of a motorboat that can move at 10 m/s in still water wishes to travel directly across a narrow strait in which the current flows at 5.0 m/s. At what angle upstream should the driver head the boat? A) 27e B) 30e C) 60e D) 63e

B

Two boxes of masses m and 3m are stacked. (See Fig. 4-6.) The surface between the more massive box and the horizontal surface is smooth and the surface between the boxes is rough. If the less massive box does not slide on the more massive box, what is the coefficient of static friction between the boxes? A) F/(4mg) B) F/(3mg) C) F/(2mg) D) F/(mg)

B

Two forces are acting on an object as shown in Fig. 3-1. What is the magnitude of the resultant force? A) 47.5 N B) 185 N C) 198 N D) 200 N

B

Two vectors A and B have components (0, 1) and (-1, 3), respectively. What are the components of the sum of these two vectors? A) (1, 4) B) (-1, 4) C) (1, 2) D) (-1, 2)

B

You are driving home on a weekend from school at 55 mi/h for 110 miles. It then starts to snow and you slow to 35 mi/h. You arrive home after driving 4 hours and 15 minutes. How far is your hometown from school? A) 180 mi B) 190 mi C) 200 mi D) 210 mi

B

A ball thrown horizontally from a point 24 m above the ground, strikes the ground after traveling horizontally a distance of 18 m. With what speed was it thrown? A) 6.1 m/s B) 7.4 m/s C) 8.1 m/s D) 8.9 m/s

C

A bullet shot straight up returns to its starting point in 10 s. What is the initial speed of the bullet? A) 9.8 m/s B) 25 m/s C) 49 m/s D) 98 m/s

C

A butterfly moves with a speed of 12.0 m/s. The x component of its velocity is 8.00 m/s. The angle between the direction of its motion and the x axis must be A) 30.0e. B) 41.8e. C) 48.2e. D) 53.0e.

C

A car goes from 40 m/s to 80 m/s in a distance of 200 m. What is its average acceleration? A) 8.0 m/s2 B) 9.6 m/s2 C) 12 m/s2 D) 24 m/s2

C

A car starting from rest moves with constant acceleration of 2.0 m/s2 for 10 s, then travels with constant speed for another 10 s, and then finally slows to a stop with constant acceleration of -2.0 m/s2. How far does it travel? A) 200 m B) 300 m C) 400 m D) 500 m

C

A car starts from rest and accelerates uniformly at 3.0 m/s2. A second car starts from rest 6.0 s later at the same point and accelerates uniformly at 5.0 m/s2. How long does it take the second car to overtake the first car? A) 12 s B) 19 s C) 21 s D) 24 s

C

A car travels 20 km West, then 20 km South. What is the magnitude of its displacement? A) 0 km B) 20 km C) 28 km D) 40 km

C

A car travels at 15 m/s for 10 s. It then speeds up with a constant acceleration of 2.0 m/s2 for 15 s. At the end of this time, what is its velocity? A) 15 m/s B) 30 m/s C) 45 m/s D) 375 m/s

C

A cart starts from rest and accelerates at 4.0 m/s2 for 5.0 s, then maintain that velocity for 10 s, and then decelerates at the rate of 2.0 m/s2 for 4.0 s. What is the final speed of the car? A) 20 m/s B) 16 m/s C) 12 m/s D) 10 m/s

C

A cart with an initial velocity of 5.0 m/s experiences a constant acceleration of 2.0 m/s2. What is the cart's displacement during the first 6.0 s of its motion? A) 10 m B) 55 m C) 66 m D) 80 m

C

A girl throws a rock horizontally, with a velocity of 10 m/s, from a bridge. It falls 20 m to the water below. How far does the rock travel horizontally before striking the water? A) 14 m B) 16 m C) 20 m D) 24 m

C

A jet fighter plane is launched from a catapult on an aircraft carrier. It reaches a speed of 42 m/s at the end of the catapult, and this requires 2.0 s. Assuming the acceleration is constant, what is the length of the catapult? A) 16 m B) 24 m C) 42 m D) 84 m

C

A jumper in the long-jump goes into the jump with a speed of 12 m/s at an angle of 20e above the horizontal. How far does the jumper jump? A) 3.4 m B) 6.2 m C) 9.4 m D) 15 m

C

A jumper in the long-jump goes into the jump with a speed of 12 m/s at an angle of 20e above the horizontal. How long is the jumper in the air before returning to the Earth? A) 0.21 s B) 0.42 s C) 0.84 s D) 1.3 s

C

A ly (light year) is the distance that light travels in one year. The speed of light is 3.00 ˛ 108 m/s. How many miles are there in a ly? (1 mi = 1609 m, 1 yr = 365 d.) A) 9.46 ˛ 1012 mi B) 9.46 ˛ 1015 mi C) 5.88 ˛ 1012 mi D) 5.88 ˛ 1015 mi

C

A plane has an air speed of 200 m/s due North, and is in a wind of 50.0 m/s to the West. The plane's speed relative to the ground is A) 150 m/s. B) 200 m/s. C) 206 m/s. D) 250 m/s.

C

A runner ran the marathon (approximately 42.0 km) in 2 hours and 57 min. What is the average speed of the runner in m/s? A) 14.2 ˛ 103 m/s B) 124 m/s C) 3.95 m/s D) 14.2 m/s

C

A student pulls a box of books on a smooth horizontal floor with a force of 100 N in a direction of 37.0e above the horizontal. If the mass of the box and the books is 40.0 kg, what is the normal force on the box? A) 292 N B) 312 N C) 332 N D) 392 N

C

A student pulls a box of books on a smooth horizontal floor with a force of 100 N in a direction of 37e above the horizontal. If the mass of the box and the books is 40.0 kg, what is the acceleration of the box? A) 1.5 m/s2 B) 1.9 m/s2 C) 2.0 m/s2 D) 3.3 m/s2

C

An airplane increases its speed from 100 m/s to 160 m/s, at the average rate of 15 m/s2. How much time does it take for the complete increase in speed? A) 17 s B) 0.058 s C) 4.0 s D) 0.25 s

C

An object has a mass of 60 kg on the Earth. What is the mass of the object on the surface of the Moon where the acceleration due to gravity is only 1/6 of that on the Earth? A) 6.0 kg B) 10 kg C) 60 kg D) 360 kg

C

An object is placed on an inclined plane. The angle of incline is gradually increased until the object begins to slide. The angle at which this occurs is q. What is the coefficient of static friction between the object and the plane? A) sin q B) cos q C) tan q D) 1/tan q

C

An object is thrown upward with a speed of 12 m/s on the surface of planet X where the acceleration due to gravity is 1.5 m/s2. What is the maximum height reached by the object? A) 8.0 m B) 18 m C) 48 m D) 144 m

C

An object of mass 6000 kg rests on the flatbed of a truck. It is held in place by metal brackets that can exert a maximum horizontal force of 9000 N. When the truck is traveling 15 m/s, what is the minimum stopping distance if the load is not to slide forward into the cab? A) 15 m B) 30 m C) 75 m D) 150 m

C

An object starts from rest and undergoes uniform acceleration. During the first second it travels 5.0 m. How far will it travel during the third second? A) 5.0 m B) 15 m C) 25 m D) 45 m

C

During the investigation of a traffic accident, police find skid marks 90.0 m long. They determine the coefficient of friction between the car's tires and the roadway to be 0.500 for the prevailing conditions. Estimate the speed of the car when the brakes were applied. A) 9.49 m/s B) 21.0 m/s C) 29.7 m/s D) 42.0 m/s

C

In Fig. 2-1, what is the velocity at t = 2.5 s? A) 0 B) 10 m/s C) 20 m/s D) -40 m/s

C

In Fig. 2-2, what is the average acceleration from 0 to 8.0 s? A) 0 B) 2.0 m/s2 C) -2.5 m/s2 D) 10 m/s2

C

In Fig. 2-2, what is the displacement from 0 to 8.0 s? A) 20 m B) 40 m C) 60 m D) 80 m

C

In Fig. 4-2, if the tensions in the ropes are 50 N, what is the mass of the traffic light? A) 3.1 kg B) 4.1 kg C) 6.1 kg D) 8.1 kg

C

In the Atwood machine shown in Fig. 4-1, if M = 0.60 kg and m = 0.40 kg, what is the magnitude of the acceleration of the system? (Ignore friction and the mass of the pulley.) A) 5.3 m/s2 B) 3.9 m/s2 C) 2.0 m/s2 D) 0.98 m/s2

C

Starting from rest, a 4.0-kg body reaches a speed of 8.0 m/s in 2.0 s. What is the net force acting on the body? A) 4.0 N B) 8.0 N C) 16 N D) 32 N

C

The coefficients of static and kinetic frictions for plastic on wood are 0.50 and 0.40, respectively. How much horizontal force would you need to apply to a 3.0 N plastic calculator to start it moving from rest? A) 0.15 N B) 1.2 N C) 1.5 N D) 2.7 N

C

The driver of a motorboat that can move at 10 m/s in still water wishes to travel directly across a river 1.6 km wide in which the current flows at 5.0 m/s. How long will it take to cross the river? A) 5.3 min B) 2.7 min C) 2.4 min D) 1.8 min

C

Two boxes of masses m and 2m are in contact with each other on a frictionless surface. (See Fig. 4-3.) What is the acceleration of the more massive box? A) F/m B) F/(2m) C) F/(3m) D) F/(4m)

C

Two boxes of masses m and 3m are stacked. (See Fig. 4-6.) The surface between the more massive box and the horizontal surface is smooth and the surface between the boxes is rough. If the less massive box does not slide on the more massive box, what is the static friction force on the less massive box? A) F B) F/2 C) F/3 D) F/4

C

Two horizontal forces act on a 5.0-kg mass. One force has a magnitude of 8.0 N and is directed due north. The second force toward the east has a magnitude of 6.0 N. What is the acceleration of the mass? A) 1.6 m/s2 due north B) 1.2 m/s2 due east C) 2.0 m/s2 at 53e N of E D) 2.0 m/s2 at 53 m E of N

C

Vector A = (1, 3). Vector B = (3, 0). Vector C = A + B . What is the magnitude of C ? A) 3 B) 4 C) 5 D) 7

C

What is the mass of an object that weighs 250 N on the surface of the Earth where the acceleration due to gravity is 9.80 m/s2? A) 250 kg B) 24.5 kg C) 25.5 kg D) 2,450 kg

C

What must be your average speed in order to travel 350 km in 5.15 h? A) 66.0 km/h B) 67.0 km/h C) 68.0 km/h D) 69.0 km/h

C

A runner runs halfway around a circular path of radius 10 m. What is the displacement of the jogger? A) 0 B) 5 m C) 10 m D) 20 m

D

A ball is thrown downward from the top of a building with an initial speed of 25 m/s. It strikes the ground after 2.0 s. How high is the building? A) 20 m B) 30 m C) 50 m D) 70 m

D

A boat can move at 30 km/h in still water. How long will it take to move 12 km upstream in a river flowing 6.0 km/h? A) 20 min B) 22 min C) 24 min D) 30 min

D

A boat, whose speed in still water is 8.0 m/s, is directed across a river with a current of 6.0 m/s. What is the speed of the boat as it crosses the river? A) 5.3 m/s B) 6.0 m/s C) 8.0 m/s D) 10.0 m/s

D

A car traveling 60 km/h accelerates at the rate of 2.0 m/s2. How much time is required for the car to reach a speed of 90 km/h? A) 15 s B) 30 s C) 45 s D) 4.2 s

D

A car travels 90 km/h. How long does it take for it to travel 400 km? A) 4.1 h B) 4.2 h C) 4.3 h D) 4.4 h

D

A person on a scale rides in an elevator. If the mass of the person is 60.0 kg and the elevator accelerates upward with an acceleration of 4.90 m/s2, what is the reading on the scale? A) 147 N B) 294 N C) 588 N D) 882 N

D

A polar bear starts at the North Pole. It travels 1.0 km south, then 1.0 km east, then 1.0 km north, then 1.0 km west to return to its starting point. This trip takes 45 min. What was the bear's average speed? A) 0 km/h B) 0.09 km/h C) 4.5 km/h D) 5.3 km/h

D

A projectile is launched with an initial velocity of 60.0 m/s at an angle of 30.0e above the horizontal. How far does it travel? A) 152 m B) 160 m C) 184 m D) 318 m

D

A stone is thrown horizontally with an initial speed of 10 m/s from the edge of a cliff. A stop watch measures the stone's trajectory time from the top of the cliff to the bottom to be 4.3 s. What is the height of the cliff? A) 22 m B) 43 m C) 77 m D) 91 m

D

A traffic light of weight 100 N is supported by two ropes as shown in Fig. 4-2. What are the tensions in the ropes? A) 50 N B) 63 N C) 66 N D) 83 N

D

An object is thrown upward with a speed of 15 m/s on the surface of planet X where the acceleration due to gravity is 2.5 m/s2. How long does it take for the object to return to where it is thrown? A) 6.0 s B) 8.0 s C) 10 s D) 12 s

D

An object with a mass m slides down a rough 37e inclined plane where the coefficient of kinetic friction is 0.20. If the plane is 10 m long and the mass starts from rest, what will be its speed at the bottom of the plane? A) 12 m/s B) 11 m/s C) 9.7 m/s D) 9.3 m/s

D

If vector A = (-3.0, -4.0) and vector B = (+3.0, -8.0), what is the magnitude of vector C = A - B ? A) 13 B) 16 C) 144 D) 7.2

D

If you are driving 72 km/h along a straight road and you look to the side for 4.0 s, how far do you travel during this inattentive period? A) 18 m B) 20 m C) 40 m D) 80 m

D

If you run a complete loop around an outdoor track (400 m), in 100 s, your average velocity is A) 0.25 m/s. B) 4.0 m/s. C) 40,000 m/s. D) zero.

D

In Fig. 2-1, what is the velocity at t = 5.5 s? A) 0 B) 10 m/s C) 20 m/s D) -40 m/s

D

In Fig. 2-2, what is the acceleration at 1.0 s? A) 0 B) 2.0 m/s2 C) -2.5 m/s2 D) 10 m/s2

D

Three vectors, expressed in Cartesian coordinates, are x comp y comp S -3.5 +4.5 T 0 -6.5 U +5.5 -2.5 What is the angle of the resultant vector S + T + U measured from the positive x axis? A) 24e above B) 24e below C) 66e above D) 66e below

D

Two boxes of masses m and 2m are connected by a rope. (See Fig. 4-4.) If the forward force on the more massive box is F, what is the tension in the connecting rope? A) 3F B) F C) F/2 D) F/3

D

Two forces are acting on an object as shown in Fig. 3-1. What is the direction of the resultant force? A) 12e above -x B) 78e above -x C) 12e above +x D) 78e above +x

D

Two vectors A and B have components (0, 1) and (-1, 3), respectively. What is magnitude of the sum of these two vectors? A) 2.8 B) 3.2 C) 3.9 D) 4.1

D

Vector A has magnitude 8.0 m at an angle of 30 degrees below the +x axis. The y component of A is A) 6.9 m. B) -6.9 m. C) 4.0 m. D) -4.0 m.

D