Physics Exam 1 MC
A bird, accelerating from rest at a constant rate, experiences a displacement of 25 m in 12 s. What is its acceleration?
0.22
A cart of weight 15.0 N is accelerated across a level surface at 0.15 m/s2. What net force acts on the wagon? (g = 9.8 m/s2)
0.23
A ball is rolled horizontally off a table with an initial speed of 0.24 m/s. A stopwatch measures the ball's trajectory time from table to the floor to be 0.36 s. What is the height of the table? (g = 9.8 m/s2 and air resistance is negligible)
0.64
A track star in the broad jump goes into the jump at 12.0 m/s and launches himself at 26.0° above the horizontal. How long is he in the air before returning to Earth? (g = 9.8 m/s2)
1.1
Two ropes are attached to a 50-kg object. The first rope applies a force of 35 N and the second, 55 N. If the two ropes are perpendicular to each other, what is the resultant acceleration of the object?
1.3
A 3 000-kg sailboat experiences an eastward force of 4 500 N by the ocean tide and a wind force against its sails with magnitude of 5 800 N directed toward the northwest (45° N of W). What is the magnitude of the resultant acceleration?
1.4
A baseball is released at rest from the top of the Washington Monument. It hits the ground after falling for 5.85 s. What was the height from which the ball was dropped? (g = 9.80 m/s2 and assume air resistance is negligible)
1.68 x 10^2
The accelerating force of the wind on a small 300-kg sailboat is 780 N northeast. If the drag of the keel is 552 N acting west, what is the acceleration of the boat?
1.8 due north
A baseball thrown from the outfield is released from shoulder height at an initial velocity of 29.1 m/s at an initial angle of 30.0° with respect to the horizontal. What is the maximum vertical displacement that the ball reaches during its trajectory?
10.8
A vehicle designed to operate on a drag strip accelerates from zero to 34 m/s while undergoing a straight-line path displacement of 48 m. What is the vehicle's acceleration if its value may be assumed to be constant?
12.04
A European sports car dealer claims that his car will accelerate at a constant rate from rest to 100 km/h in 8.00 s. If so, what is the acceleration? (Hint: First convert speed to m/s.)
12.5
A stone is thrown at an angle of 30° above the horizontal from the top edge of a cliff with an initial speed of 12 m/s. A stop watch measures the stone's trajectory time from top of cliff to bottom to be 4.8 s. What is the height of the cliff? (g = 9.8 m/s2 and air resistance is negligible)
124
A bridge that was 10.4 m long has been washed out by the rain several days ago. How fast must a car be going to successfully jump the stream, if we neglect air resistance? Although the road is level on both sides of the bridge, the road on the far side is 3.00 m lower than the road on this side.
13.3
A 60.0-kg man jumps 1.70 m down onto a concrete walkway. His downward motion stops in 0.025 seconds. If he forgets to bend his knees, what force is transmitted to his leg bones?
13900
The acceleration due to gravity on the Moon's surface is one-sixth that on Earth. What net force would be required to accelerate a 25.0-kg object at 5.80 m/s2 on the Moon?
145
A ball is pushed with an initial velocity of 4.0 m/s. The ball rolls down a hill with a constant acceleration of 1.7 m/s2. The ball reaches the bottom of the hill in 7.0 s. What is the ball's velocity at the bottom of the hill?
15.9
John throws a baseball from the outfield from shoulder height, at an initial velocity of 41.5 m/s at an initial angle of 40.0° with respect to the horizontal. The ball is in its trajectory for a total interval of 5.00 s before the third baseman catches it at an equal shoulder-height level. (Assume air resistance negligible.) What is the ball's horizontal displacement?
159
Human reaction time is usually about 0.18 s. If your lab partner holds a ruler between your finger and thumb and releases it without warning, how far can you expect the ruler to fall before you catch it? The nearest value is
16
A shot-putter moves his arm and the 6.00-kg shot through a distance of 1.25 m, giving the shot a velocity of 8.20 m/s from rest. Find the average force exerted on the shot during this time.
161
A 2 000-kg sailboat experiences an eastward force of 4 500 N by the ocean tide and a wind force against its sails with magnitude of 1 500 N directed toward the northwest (45° N of W). What is the direction of the resultant acceleration?
17* N of E
The distance of the Earth from the Sun is 93 000 000 miles. If there are 3.15 × 107 s in one year, find the speed of the Earth in its orbit about the Sun.
18.6
A 3.0-kg bowling ball experiences a net force of 8.0 N. What will be its acceleration?
2.7
A Cessna aircraft has a lift-off speed of 135 km/h. What minimum constant acceleration does this require if the aircraft is to be airborne after a take-off run of 260 m?
2.70
John throws a rock down with speed 11 m/s from the top of a 25-m tower. If g = 9.8 m/s2 and air resistance is negligible, what is the rock's speed just as it hits the ground?
25
Gwen releases a rock at rest from the top of a 40-m tower. If g = 9.8 m/s2 and air resistance is negligible, what is the speed of the rock as it hits the ground?
28
Wiley Coyote has missed the elusive road runner once again. This time, he leaves the edge of the cliff at 52.4 m/s horizontal velocity. If the canyon is 140 m deep, how far from his starting point at the edge of the cliff does the coyote land?
280
Rita accelerates a 0.50-kg ball from rest to 8.0 m/s during the 0.14 s in which her foot is in contact with the ball. What average force does she apply to the ball during the kick?
29
When a drag strip vehicle reaches a velocity of 65.0 m/s, it begins a negative acceleration by releasing a drag chute and applying its brakes. While reducing its velocity back to zero, its acceleration along a straight-line path is a constant −7.10 m/s2. What displacement does it undergo during this deceleration period?
298
A speeding car traveling at a constant velocity of v passes a police car initially at rest beside the roadway. If the police car with constant acceleration of a immediately pursues the speeding car, how long is it before the police car is directly behind the speeding car?
2v/a
A bird, accelerating from rest at a constant rate, experiences a displacement of 25 m in 15 s. What is the final velocity after 15 s?
3.33
Omar throws a rock down with speed 12.5 m/s from the top of a tower. The rock hits the ground after 1.50 s. What is the height of the tower? (air resistance is negligible)
30.0
A rock, released at rest from the top of a tower, hits the ground after 3.5 s. What is the speed of the rock as it hits the ground? (g = 9.8 m/s2 and air resistance is negligible)
34
An automobile of mass 2 500 kg moving at 50.0 m/s is braked suddenly with a constant braking force of 8 500 N. How far does the car travel before stopping?
368
A speeding car traveling at a constant velocity of 24 m/s passes a police care initially at rest beside the roadway. If the police car with constant acceleration of 3.0 m/s2 immediately pursues the speeding car, how far down the road does it draw even with the speeding car?
380
A barefoot field-goal kicker imparts a speed of 30 m/s to a football at rest. If the football has a mass of 0.45 kg and time of contact with the football is 0.035 s, what is the force exerted on the foot?
390
The statement by Newton that "for every action there is an opposite but equal reaction" is regarded as which of his laws of motion?
3rd
The acceleration due to gravity on the Moon's surface is one-sixth that on Earth. An astronaut's life support backpack weighs 250 lb on Earth. What does it weigh on the Moon?
41.7
Two forces act on a 8.50-kg object. One of the forces is 14.0 N. If the object accelerates at 3.50 m/s2, what is the greatest possible magnitude of the other force?
43.8
A projectile is fired directly upwards at 49.4 m/s. A second projectile is dropped from rest at some higher elevation at the instant the first projectile is fired and passes the first projectile 3.00 s later. From the frame of reference of the first projectile, what is the velocity of the second projectile as it passes by?
49.4, downward
A baseball leaves the bat with a speed of 47 m/s and an angle of 45° above the horizontal. A 5.0-m-high fence is located at a horizontal distance of 137 m from the point where the ball is struck. Assuming the ball leaves the bat 1.0 m above ground level, by how much does the ball clear the fence?
49.7
An automobile driver puts on the brakes and decelerates from 35.0 m/s to zero in 11.0 s. What distance does the car travel?
5.6
A stone is thrown at an angle of 30° above the horizontal from the top edge of a cliff with an initial speed of 8.0 m/s. A stop watch measures the stone's trajectory time from top of cliff to bottom to be 5.9 s. How far out from the cliff's edge does the stone travel horizontally? (g = 9.8 m/s2 and air resistance is negligible)
50.0
A ball is launched from ground level at 25 m/s at an angle of 31° above the horizontal. How far does it go before it is at ground level again?
56
A jet airliner moving at 470 mph due east moves into a region where the wind is blowing at 110 mph in a direction 30.0° north of east. What is the new velocity and direction of the aircraft?
568, 10.4 N of E
A baseball batter hits an incoming 45.0-m/s fastball. The ball leaves the bat at 56.0 m/s after a ball-on-bat contact time of 0.040 s. What is the force exerted on the 0.25-kg baseball?
631
An astronaut applies a force of 450 N to an asteroid, and it accelerates at 7.0 m/s2. What is the asteroid's mass?
64
A cart is given an initial velocity of 5.0 m/s and experiences a constant acceleration of 2.4 m/s2. What is the magnitude of the cart's displacement during the first 5.0 s of its motion?
68.2
A drag racer starts from rest and accelerates at 8.0 m/s2 for the entire distance of 300 m. What is the velocity of the race car at the end of the run?
69
A railroad train travels forward along a straight track at 90.0 m/s for 1 000 m and then travels at 70.0 m/s for the next 1 000 m. What is the average velocity?
78.7
A rifle is aimed horizontally toward the center of a target 120 m away. If the bullet strikes 11.2 cm below the center, what was the velocity of the bullet? (Ignore air friction.)
790
A cheetah can maintain its maximum speed of 96.0 km/hr for 26.0 seconds. What minimum distance must a gazelle running 85.0 km/hr be ahead of the cheetah to escape?
91.7
Which of the following is an example of the type of force that acts at a distance?
Gravitational, Magnetic, Electrical
Which of the following expresses a principle, which was initially stated by Galileo and was later incorporated into Newton's laws of motion?
The natural condition for a moving object is to remain in motion.
If we know an object is moving at constant velocity, we may assume:
The net force acting on the object is zero.
A physics student is riding on a train traveling north. Having read about inertia, the student performs an experiment with a golf ball. He reaches over the aisle and drops the ball from rest. Instead of hitting the floor directly below the student's hand, it hits to the north, i.e., forward of that position. Which of the following might be the cause for this to happen?
The train is slowing down.
A baseball is thrown by the center fielder (from shoulder level) to home plate where it is caught (on the fly at shoulder level) by the catcher. At what point does the magnitude of the vertical component of velocity have its minimum value? (air resistance is negligible)
acceleration is constant during entire trajectory
The net force on an object is in the positive x-direction. Consider the following statements. (I) The object can be moving in the negative x-direction. (II) The object can be speeding up. (III) The object can be slowing down. (IV) The object can be moving in the positive y-direction. Which of the statements are true?
all are true
Jeff throws a ball straight up. For which situation is the vertical velocity zero?
at the top
A baseball is thrown by the center fielder (from shoulder level) to home plate where it is caught (on the fly at shoulder level) by the catcher. At what point is the magnitude of the acceleration at a minimum? (air resistance is negligible)
at the top of the trajectory
On a position-versus-time graph, the slope of the straight line joining two points on the plotted curve that are separated in time by the interval Δt, is which of the following quantities?
average velocity
If we know that a nonzero net force is acting on an object, which of the following must we assume regarding the object's condition? The object is:
being accelerated
In the case of constant acceleration, the average velocity equals the instantaneous velocity:
half way thru the time interval
What condition must apply to a system's state of motion for it to be regarded as an inertial frame of reference?
in constant velocity
A plane is moving due north, directly towards its destination. Its airspeed is 220 mph. A constant breeze is blowing from west to east at 50 mph. How long will it take for the plane to travel 220 miles north?
more than an hour
A ball is thrown vertically upwards at 19.0 m/s. For its complete trip (up and back down to the starting position), its average velocity is:
not given bc the average velocity would be 0
If the displacement of an object is given in SI units by Δx = −3t + 4t 2, at t = 2 s its velocity and acceleration are, respectively:
positive, positive
Changing the positive direction in a reference frame to the opposite direction does not change the sign of which of the following quantities?
speed
A strobe photograph shows equally-spaced images of a car moving along a straight road. If the time intervals between images is constant, which of the following cannot be positive?
the acceleration of the car
A strobe photograph of a car moving along a straight road shows the interval between each successive image to be diminishing. If the direction of motion of the car is taken as positive, which of the following is/are negative?
the average acceleration of the car
A thrown stone hits a window, but doesn't break it. Instead it reverses direction and ends up on the ground below the window. In this case, we know:
the force of the stone on the grass = the force of the glass on the stone.
Consider the magnitude of the average speed, vavg, speed, mag, and the magnitude of the average velocity, vavg, velocity, mag, for the same trip. Which of the following is always true?
vavg, speed, mag ≥ vavg, velocity, mag
In the terminology a 500-N block, the 500-N refers to the block's:
weight
A baseball thrown from the outfield is released from shoulder height at an initial velocity of 28.3 m/s at an initial angle of 30.0° with respect to the horizontal. If it is in its trajectory for a total of 4.00 s before being caught by the third baseman at an equal shoulder-height level, what is the ball's net vertical displacement during its 4.00-s trajectory?
zero
