physics: testwizard midterm
The diagram below shows an 8.0-kilogram cart moving to the right at 4.0 meters per second about to make a head-on collision with a 4.0-kilogram cart moving to the left at 6.0 meters per second.After the collision , the 4.0-kilogram cart moves to the right at 3.0 meters per second. What is the velocity of the 8.0-kilogram cart after the collision? A) 0.50 m/s left B) 0.50 m/s right C) 5.5 m/s left D) 5.5 m/s right
A
the diagram below which shows a ball projected horizontally with an initial velocity of 20. meters per second east, off a cliff 100. meters high. [Neglect air resistance.]During the flight of the ball, what is the direction of its acceleration? A) downward B) upward C) westward D) eastward
A
the diagram below which shows a ball projected horizontally with an initial velocity of 20. meters per second east, off a cliff 100. meters high. [Neglect air resistance.]How many seconds does the ball take to reach the ground? A) 4.5 s B) 20. s C) 9.8 s D) 2.0 s
A
A 0.25-kilogram baseball is thrown upward with a speed of 30. meters per second. Neglecting friction, the maximum height reached by the baseball is approximately A) 15 m B) 46 m C) 74 m D) 92 m
B
A 0.45-kilogram football traveling at a speed of 22 meters per second is caught by an 84-kilogram stationary receiver. If the football comes to rest in the receiver's arms, the magnitude of the impulse imparted to the receiver by the ball is A) 1800 N•s B) 9.9 N•s C) 4.4 N•s D) 3.8 N•s
B
A 2.0-kilogram laboratory cart is sliding across a horizontal frictionless surface at a constant velocity of 4.0 meters per second east. What will be the cart's velocity after a 6.0-newton westward force acts on it for 2.0 seconds? A) 2.0 m/s east B) 2.0 m/s west C) 10. m/s east D) 10. m/s west
B
A 3.0-kilogram object is acted upon by an impulse having a magnitude of 15 newton•seconds. What is the magnitude of the object's change in momentum due to this impulse? A) 5.0 kg•m/s B) 15 kg•m/s C) 3.0 kg•m/s D) 45 kg•m/s
B
A 4.0-kilogram object is accelerated at 3.0 meters per second2 north by an unbalanced force. The same unbalanced force acting on a 2.0-kilogram object will accelerate this object toward the north at A) 12 m/s2 B) 6.0 m/s2 C) 3.0 m/s2 D) 1.5 m/s2
B
A 5.0-kilogram box is sliding across a level floor. The box is acted upon by a force of 27 newtons east and a frictional force of 17 newtons west. What is the magnitude of the acceleration of the box? A) 0.50 m/s2 B) 2.0 m/s2 C) 8.8 m/s2 D) 10. m/s2
B
A 5.00-kilogram block slides along a horizontal, frictionless surface at 10.0 meters per second for 4.00 seconds. The magnitude of the block's momentum is A) 200. kg•m/s B) 50.0 kg•m/s C) 20.0 kg•m/s D) 12.5 kg•m/s
B
A 6.0-kilogram block, sliding to the east across a horizontal, frictionless surface with a momentum of 30. kilogram•meters per second, strikes an obstacle. The obstacle exerts an impulse of 10. newton•seconds to the west on the block. The speed of the block after the collision is A) 1.7 m/s B) 3.3 m/s C) 5.0 m/s D) 20. m/s
B
A ball is thrown horizontally at a speed of 20. meters per second from the top of a cliff. How long does the ball take to fall 19.6 meters to the ground? A) 1.0 s B) 2.0 s C) 9.8 s D) 4.0 s
B
A net force of 10. Newtons accelerates an object at 5.0 meters per second2. What net force would be required to accelerate the same object at 1.0 meter per second2? A) 1.0 N B) 2.0 N C) 5.0 N D) 50. N
B
A person weighing 785 newtons on the surface of Earth would weigh 298 newtons on the surface of Mars. What is the magnitude of the gravitational field strength on the surface of Mars? A) 2.63 N/kg B) 3.72 N/kg C) 6.09 N/kg D) 9.81 N/kg
B
A runner completed the 100.-meter dash in 10.0 seconds. Her average speed was A) 0.100 m/s B) 10.0 m/s C) 100. m/s D) 1,000 m/s
B
An object is dropped from rest and falls freely 20. meters to Earth. When is the speed of the object 10 meters per second? A) during the entire first second of its fall B) at the end of its first second of fall C) during its entire time of fall D) after it has fallen 9.8 meters
B
As a constant unbalanced force acts on an object in the direction of motion, the object's speed A) decreases B) increases C) remains the same
B
How would the mass and weight of an object on the Moon compare to the mass and weight of the same object on Earth? A) Mass and weight would both be less on the Moon. B) Mass would be the same but its weight would be less on the Moon. C) Mass would be less on the Moon and its weight would be the same. D) Mass and weight would both be the same on the Moon.
B
Objects A and B are dropped from rest near Earth's surface. Object A has mass m and object B has mass 2m. After 2 seconds of free fall, object A has a speed v and has fallen a distance d. What are the speed and distance of fall of object B after 2 seconds of free fall? A) speed = v/2; distance = d/2 B) speed = v; distance = d C) speed = v/2; distance = 2d D) speed = 2v; distance = 2d
B
The average speed of a runner in a 400.-meter race is 8.0 meters per second. How long did it take the runner to complete the race? A) 80. sec B) 50. sec C) 40. sec D) 32. sec
B
The diagram below shows a horizontal 8.0-newton force applied to a 4.0-kilogram block on a frictionless table.What is the magnitude of the block's acceleration? A) 0.50 m/s2 B) 2.0 m/s2 C) 9.8 m/s2 D) 32 m/s2
B
What is the speed of a 1.0 × 103-kilogram car that has a momentum of 2.0 × 104 kilogram • meters per second east? A) 5.0 ×10-2 m/s B) 2.0 × 101 m/s C) 1.0 × 104 m/s D) 2.0 × 107 m/s
B
Which property of an object must double in order to double its weight? A) kinetic energy B) mass C) momentum D) velocity
B
Which quantity has both a magnitude and a direction? A) energy B) impulse C) power D) work
B
A 1.0-kilogram laboratory cart moving with a velocity of 0.50 meter per second due east collides with and sticks to a similar cart initially at rest. After the collision, the two carts move off together with a velocity of 0.25 meter per second due east. The total momentum of this frictionless system is A) zero before the collision B) zero after the collision C) the same before and after the collision D) greater before the collision than after the collision
C
A 40.-kilogram mass is moving across a horizontal surface at 5.0 meters per second. What is the magnitude of the net force required to bring the mass to a stop in 8.0 seconds? A) 1.0 N B) 5.0 N C) 25 N D) 40. N
C
A 75-kilogram hockey player is skating across the ice at a speed of 6.0 meters per second. What is the magnitude of the average force required to stop the player in 0.65 second? A) 120 N B) 290 N C) 690 N D) 920 N
C
A ball is rolling horizontally at 3.00 meters per second as it leaves the edge of a tabletop 0.750 meter above the floor. The ball lands on the floor 0.391 second after leaving the tabletop. What is the magnitude of the ball's acceleration 0.200 second after it leaves the tabletop? [Neglect friction.] A) 1.96 m/s2 B) 7.65 m/s2 C) 9.81 m/s2 D) 15.3 m/s2
C
A man weighing 800 Newtons is standing in an elevator. If the elevator rises with an acceleration of 9.8 meters per second2, the force exerted by the elevator on the man will be A) 400 N B) 800 N C) 1600 N D) 2000 N
C
A rock dropped off a bridge takes 5 seconds to hit the water. Approximately what was the rock's velocity just before impact? A) 5 m/s B) 2 m/s C) 50 m/s D) 125 m/s
C
A rock is thrown horizontally from the top of a cliff at 12 meters per second. Approximately how long does it take the rock to fall 45 meters vertically? [Assume negligible air resistance.] A) 1.0 s B) 5.0 s C) 3.0 s D) 8.0 s
C
A student on an amusement park ride moves in a circular path with a radius of 3.5 meters once every 8.9 seconds. The student moves at an average speed of A) 0.39 m/s B) 1.2 m/s C) 2.5 m/s D) 4.3 m/s
C
Ball A of mass 5.0 kilograms moving at 20. meters per second collides with ball B of unknown mass moving at 10. meters per second in the same direction. After the collision, ball A moves at 10. meters per second and ball B at 15 meters per second, both still in the same direction. What is the mass of ball B? A) 6.0 kg B) 2.0 kg C) 10. kg D) 12 kg
C
How far will a brick starting from rest fall freely in 3.0 seconds? A) 15 m B) 29 m C) 44 m D) 88 m
C
In a drill during basketball practice, a player runs the length of the 30.-meter court and back. The player does this three times in 60. seconds.The average speed of the player during the drill is A) 0.0 m/s B) 0.50 m/s C) 3.0 m/s D) 30. m/s
C
In the diagram below, a box is on a frictionless horizontal surface with forces F1 and F2 acting shown. If the magnitude of F1 is greater than the magnitude of F2 , then the box is A) moving at constant speed in the direction of F1 B) moving at constant speed in the direction of F2 C) accelerating in the direction of F1 D) accelerating in the direction of F2
C
On a highway, a car is driven 80. kilometers during the first 1.00 hour of travel, 50. kilometers during the next 0.50 hour, and 40. kilometers in the final 0.50 hour. What is the car's average speed for the entire trip? A) 45 km/h B) 60. km/h C) 85 km/h D) 170 km/h
C
Which object has the greatest momentum? A) a 12-kg mass moving at 1 m/sec B) a 5-kg mass moving at 2 m/sec C) a 9-kg mass moving at 3 m/sec D) a 4-kg mass moving at 4 m/sec
C
A 0.149-kilogram baseball, initially moving at 15 meters per second, is brought to rest in 0.040 second by a baseball glove on a catcher's hand. The magnitude of the average force exerted on the ball by the glove is A) 2.2 N B) 2.9 N C) 17 N D) 56 N
D
A baseball pitcher throws a fastball at 42 meters per second. If the batter is 18 meters from the pitcher, approximately how much time does it take for the ball to reach the batter? A) 1.9 s B) 2.3 s C) 0.86 s D) 0.43 s
D
A baseball player runs 27.4 meters from the batter's box to first base, overruns first base by 3.0 meters, and then returns to first base. Compared to the total distance traveled by the player, the magnitude of the player's total displacement from the batter's box is A)3.0 m shorter B) 6.0 m shorter C) 3.0 m longer D) 6.0 m longer
D
A baseball player throws a ball horizontally. Which statement best describes the ball's motion after it is thrown? [Neglect the effect of friction.] A) Its vertical speed remains the same, and its horizontal speed increases. B) Its vertical speed remains the same, and its horizontal speed remains the same .C) Its vertical speed increases, and its horizontal speed increases. D) Its vertical speed increases, and its horizontal speed remains the same.
D
A force of 6.0 newtons changes the momentum of a moving object by 3.0 kilogram•meters per second. How long did the force act on the mass? A) 1.0 s B) 2.0 s C) 0.25 s D) 0.50 s
D
A high-speed train in Japan travels a distance of 300. kilometers in 3.60 × 103 seconds. What is the average speed of this train? A) 1.20 × 10-2 m/s B) 8.33 × 10-2 m/s C) 12.0 m/s D) 83.3 m/s
D
A projectile with mass m is fired with initial horizontal velocity vx from height h above level ground. Which change would have resulted in a greater time of flight for the projectile? [Neglect friction.] A) decreasing the mass to m/2 B) decreasing the height to h/2 C) increasing the initial horizontal velocity to 2vx D) increasing the height to 2h
D
A rock is dropped from a bridge. What happens to the magnitude of the acceleration and the speed of the rock as it falls? [Neglect friction.] A) Both acceleration and speed increase. B) Both acceleration and speed remain the same. C) Acceleration increases and speed decreases. D) Acceleration remains the same and speed increases.
D
A rock is dropped from a bridge. What happens to the value of the acceleration and the speed of the rock as it falls? [Neglect friction.] A) Both acceleration and speed increase. B) Both acceleration and speed remain the same. C) Acceleration increases and speed decreases. D) Acceleration remains the same and speed increases.
D
Cart A has a mass of 2 kilograms and a speed of 3 meters per second. Cart B has a mass of 3 kilograms and a speed of 2 meters per second. Compared to the inertia and magnitude of momentum of cart A, cart B has A) the same inertia and a smaller magnitude of momentum B) the same inertia and the same magnitude of momentum C) greater inertia and a smaller magnitude of momentum D) greater inertia and the same magnitude of momentum
D
One car travels 40. meters due east in 5.0 seconds, and a second car travels 64 meters due west in 8.0 seconds. During their periods of travel, the cars definitely had the same A) average velocity B) total displacement C) change in momentum D) average speed
D
What is the average velocity of a car that travels 30. kilometers due west in 0.50 hour? A) 15 km/hr B) 60. km/hr C) 15 km/hr west D) 60. km/hr west
D
What is the weight of a 2.00-kilogram object on the surface of Earth? A) 5.00 N B) 2.00 N C) 10.00 N D) 20.00 N
D
Which is a unit of momentum? A) N-m/s2 B) kg-m/s2 C) N-m/s D) kg-m/s
D
Which is constant for a freely falling object? A) displacement B) speed C) velocity D) acceleration
D
coefficient of friction equation
F(friction) = coefficient(force norm)
vector
a quantity that is conscious of direction
scalar
a quantity that is not conscious of direction
Inertia
direct relationship with mass (big inertia, big mass)
average velocity formula
displacement/time
displacement
distance between an object's final and initial positions
A 1000.-kilogram car traveling 20.0 meters per second east experiences an impulse of 2000. newton • seconds west. What is the final velocity of the car after the impulse has been applied? A) 18.0 m/s east B) 19.5 m/s east C) 20.5 m/s west D) 22.0 m/s west
A
A 12.0-kilogram cart is moving at a speed of 0.25 meter per second. After the speed of the cart is tripled, the inertia of the cart will be A) unchanged B) one-third as great C) three times greater D) nine times greater
A
A 2.0-kilogram ball traveling north at 4.0 meters per second collides head on with a 1.0-kilogram ball traveling south at 8.0 meters per second. What is the magnitude of the total momentum of the two balls after collision? A) 0 kg-m/s B) 8.0 kg-m/s C) 16 kg-m/s D) 32 kg-m/s
A
A book is pushed with an initial horizontal velocity of 5.0 meters per second off the top of a desk. What is the initial vertical velocity of the book?A) 0 m/s B) 2.5 m/s C) 5.0 m/s D) 10. m/s
A
A golf club hits a stationary 0.050-kilogram golf ball with an average force of 5.0 × 103 newtons, accelerating the ball to a speed of 44 meters per second. What is the magnitude of the impulse imparted to the ball by the golf club? A)2.2 ns B)880ns C)1.1 x 10^4ns D)2.2x10^5 ns
A
A group of bike riders took a 4.0-hour trip. During the first 3.0 hours, they traveled a total of 50. kilometers, but during the last hour they traveled only 10. kilometers. What was the group's average speed for the entire trip? A) 15 km/hr B) 30. km/hr C) 40. km/hr D) 60. km/hr
A
A red ball and a green ball are simultaneously thrown horizontally from the same height. The red ball has an initial speed of 40. meters per second and the green ball has an initial speed of 20. meters per second. Compared to the time it takes the red ball to reach the ground, the time it takes the green ball to reach the ground will be A) the same B) twice as much C) half as much D) four times as much
A
An air bag is used to safely decrease the momentum of a driver in a car accident. The air bag reduces the magnitude of the force acting on the driver by A) increasing the length of time the force acts on the driver B) decreasing the distance over which the force acts on the driver C) increasing the rate of acceleration of the driver D) decreasing the mass of the driver
A
An unbalanced force of 10 Newtons acts on a 20-kilogram mass for 5 seconds. The acceleration of the mass is A) 0.5 m/s2 B) 2 m/s2 C) 40 m/s2 D) 200 m/s2
A
If a block is in equilibrium, the magnitude of the block's acceleration is A) zero B) decreasing C) increasing D) constant, but not zero
A
If a car is traveling at an average speed of 60 kilometers per hour, how long does it take to travel 12 kilometers? A) 0.2 hour B) 0.5 hour C) 0.72 hour D) 5.0 hours
A
instantaneous speed
the speed of an object at a given instant
what is an essential characteristic of an object in equilibrium?
zero acceleration
