Physics Module

1. On a sunny day, a tall building casts a shadow that s 67.2 m long. The angle between the sun’s rays and the ground is θ = 50.0˚. Determine the height of the building

1. 43.2 m                                c.  80.0 m
2. 51.5 m                                d. 56.2 m

For numbers 2 and 3, refer to the question and figure below.[pic 1]

A lakefront drops off gradually at an angle θ, as the figure at the right indicates. For safety reasons, it is necessary to know how deep the lake is at various distances from the shore. To provide some information about the depth, a lifeguard rows straight out from the shore a distance of 14.0 m and drops a weighted fishing line. By measuring the length of the line, the lifeguard determines the depth to be 2.25 m.

1. What is the value of θ?

1. 42.6˚                                c.  21.0˚
2. 9.13˚                                d.  12.7˚

1. What would be the depth d of the lake at a distance 22.0 m from above?

1. 20.2 m                                c.  4.96 m
2. 8.44 m                         d.  3.54 m

1. A displacement r has a magnitude of r = 175 m and points at an angle of 50.0˚ relative to the x-axis. Find the x and y (x,y) components of this vector.

1. 112 m, 134 m                        c.   121 m, 143 m
2. 120 m, 115 m                        d.   101 m, 186 m

1. It is the distance traveled divided by the time required to cover the distance.

1. Instantaneous velocity                c.   Average velocity
2. Average speed                d.   Instantaneous speed

1. How far does a jogger run in 1.5 hours if his average speed is 2.22 m/s?

1. 3.33 m                                c.   12,000 m
2. 1.48 m                                d.   2432 m

1. Suppose a plane starts from rest (v˳ = 0 m/s) when t˳ = 0. The plane accelerates down the runway and at  t = 29 s attains a velocity of v = +260 km/h, where the plus sign indicates that the velocity points to the right. Determine the average acceleration of the plane.

1. -9.0                         c.   9.0[pic 2][pic 3]
2. 7.0                          d.   -7.0 [pic 4][pic 5]

1. A speedboat has a constant acceleration of +2.0 m/s2. If the initial velocity of the boat is +6.0 m/s, find the boat’s displacement after 8.0 seconds.

1. +110 m                        c.   +50 m
2. -110 m                                d.   -50 m

1. A spacecraft is travelling with a velocity of +3250 m/s. Suddenly the retrorockets are fired, and the spacecraft begin to slow down with an acceleration whose magnitude is 10.0 m/s2. What is the velocity of the spacecraft when the displacement of the craft is +215 km, relative to the point where the retrorockets began firing?

1. +2500 m/s                        c.   +1500 m/s
2. -2500 m/s                        d.   -1000 m/s

1. A stone is dropped from rest from the top of a tall building. After 3.00 s of free-fall, what is the displacement y of the stone?

1. -44.1 m                        c.   -7.90 m
2. +44.1 m                        d.   +7.90 m

1. After the 3.00 s of free-fall in number 10, what is the velocity of the stone?

1. +21.7 m/s                        c.   -33.4 m/s
2. -54.2 m/s                        d.   -29.4 m/s

1. A football game customarily begins with a toss coin to determine who kicks off. The referee tosses the coin up with an initial speed of 5.00 m/s. In the absence of air resistance, how high does the coin go above its point of release?

1. 2.32 m                                c.   1.28 m
2. 1.55 m                                d.   2.56 m

1. What is the total time the coin is in the air before returning to its release point in number 12?

1. 1.02 s                                c.   1.78 s
2. 0.510 s                                d.   2.13 s

For numbers 14 and 15, refer to the question below.

A skydiver is falling straight down, along the negative y direction. During the initial part of the fall, her speed increases from 16 to 28 m/s in 1.5 s. Later, her parachute opens, and her speed decreases from 48 to 26 m/s in 11 s.

1. What is the magnitude and direction of the skydiver’s average acceleration during the initial part of her fall?

1. +16 m/s2                        c.   -29 m/s2
2. -8.0 m/s2                         d.   -32 m/s2

1. What is the magnitude and direction of the skydiver’s average acceleration after her parachute opened?

1. -4.0 m/s2                        c.   +6.0 m/s2
2. +2.0 m/s2                        d.   + 8.0 m/s2

1. An airplane moving horizontally with a constant velocity of +115 m/s at an altitude of 1050 m. The directions to the right and upward have been chosen as the positive directions. The plane releases a package that falls to the ground along a curved trajectory. Ignoring air resistance, determine the time required for the package to hit the ground.

1. 10.35 s                                c.   11.2 s
2. 15.2 s                                d.   14.6 s

1. A placekicker kicks a football at an angle of θ = 40.0˚ above the horizontal axis. The initial speed of the ball is 22 m/s. Ignore air resistance, and find the maximum height H that the ball attains.

1. +11 m                                c.   +10 m
2. – 10 m                                d.   -12 m

1. Calculate the range R of the projectile in number 17.

1. -44 m                                c.   -20 m
2. +36 m                                d.   +49 m

1. This is the push or pull contact to an object. Force
2. Give the SI unit for force. [pic 6]
3. Two people are pushing a stalled car. The mass of the car is 1850 kg. One person applies a force of 275 N to the car, while the other applies a force of 395 N. Both forces act in the same direction. A third fore of 560 N also acts on the car, but in the opposite direction to that in which people are pushing. This force arises because of friction and the extent to which the pavement opposes the motion of tires. Find the car’s acceleration.

1. +0.59 m/s2                        c.   +0.65 m/s2
2. +0.059 m/s2                        d.   +0.071 m/s2

1. Suppose that the mass of a spacecraft is 11,000 kg and that the mass of an astronaut is 92 kg. the astronaut is pushing the spacecraft with force +P and the spacecraft pushes back the astronaut with force –P. In addition, assume that the astronaut exerts a force of P = +36 N on the spacecraft. Find acceleration of spacecraft.

1. +0.0033 m/s2                        c.   -0.050 m/s2
2. +0.33 m/s2                        d.   + 0.17 m/s2

1. What is the acceleration of the astronaut in number 22?

1. +0.39 m/s2                        c.   +0.52 m/s2
2. –0.39 m/s2                        d.   +0.78 m/s2

1. Two particles whose masses are m1 and m2 are attracted by gravitational forces +F and –F. What is the magnitude of the gravitational force that acts on each particle assuming m1 = 12 kg, m2 =25 kg, and r = 1.2 m?

1. 1.4 x 10 -8 N                        c.   2.1 x 10 -6 N
2. 1.9 x 10 -9 N                        d.   9.5 x 10 -7 N

1. This force is parallel to the surface but opposite to the direction of movement of a moving object. Friction
2. A truck is hauling a trailer along a level road. The mass of the truck is m1 = 500 kg and that of the trailer is m2 = 27000 kg. The two move along the x-axis with an acceleration of 0.78 m/s2. Ignoring the retarding forces of friction and air resistance, determine tension in the horizontal drawbar between the trailer and truck.

1. 16000 N                        c.   21000 N
2. 18250 N                        d.   24500 N

1. Find the work done by a 45.0-N force in pulling a suitcase at an angle θ = 50.0˚ for a distance 75.0 m.

1. 2800 J                                c.   2170 J
2. 1570 J                                d.   3200 J

1. You throw a ball with a mass of 0.40 kg against a brick wall. It hits the wall moving horizontally to the left at 30 m/s and rebounds horizontally to the right at 20 m/s. Find impulse of the net force on the bball during its collision with the wall.

1. 20 Ns                                c.   11 Ns
2. 16 Ns                                d.   22 Ns

1. If the ball in number 28 is in contact with the wall for 0.010 s, find the average horizontal force that the wall exerts on the ball during impact.

1. 1285 N                                c.   2000 N
2. 2950 N                                d.   3500 N

1. How many joules of energy does a 100-watt light bulb use per hour?

1. 6.3 x 10 7 N                        c.   4.7 x 10 5 N
2. 3.6 x 10 5 N                        d.   2.4 x 10 7 N

1. How fast would a 70-kg person have to run to amount of computed kinetic energy in number 30?

1. 28 m/s                                c.   101 m/s
2. 82 m/s                                d.   44 m/s

1. A farmer hitches her tractor to a sled loaded with firewood and pulls it a distance of 20 m along level ground. The total weight of sled is 14,700 N. The tractor exerts a constant 5000N force at an angle of 36.9˚ above horizontal. A 3500-N friction force opposes the sled’s motion. Find work done by friction.

1. -62500 J                        c.   +80000 J
2. +78000 J                        d.   -70000 J

1. Find the work done by tension in number 32.

1. -62500 J                        c.   +80000 J
2. +78000 J                        d.   -70000 J

1. A worker applies a constant horizontal force with magnitude 20 N to a box with mass 40 kg resting on a level floor with negligible friction. What is the acceleration of the box?

1. 0.32 m/s2                        c.   0.81 m/s2
2. 0.43 m/s2                        d.   0.50 m/s2

1. A gymnast with mass suspends herself from the lower end of a hanging rope of negligible mass. The upper end of the rope is attached to the gymnasium ceiling. What force (magnitude and direction) does the rope exert on her?

1. +490 N                        c.   +356 N
2. -520 N                                d.   +410 N