PHYS Test 1
An apple weighs 1 N. When at rest, at equilibrium, in the tree, the net force on the apple is
0 N
The force of friction on an object that is sliding is 10 N. The force that must be applied to the object, for the object to maintain a constant velocity is
10 N
A brick with a mass of 10 kg on the earth is taken by astronauts to the moon, where it would be
10 kg
A 10-kg and a 1-kg book are dropped in a vacuum. The force of gravity on the 10-kg brick is __________________ as that on the 1 kg book.
10 times as much
Regarding the ball in the previous question, what is its average velocity at end of the first 5 seconds?
100
After 5 seconds, how far has the ball in the previous question actually fallen?
125 m
An apple at rest weighs 15 N. The net force on the apple when it is in free fall.
15 N
If the car's speed in the previous question is increased to 4 times its original speed, the car's new kinetic energy will be __________ times its original kinetic energy.
16
An object lifted 10 meters gains 50 J of potential energy. If the same object is lifted 5 meters, its potential energy gain is
25 J
A driver travels 50 miles in his first hour, then 50 more miles in each of the following 5 hours, for a total of 300 miles traveled. What was his acceleration in miles per hour, per hour, over the 6 hours of travel?
300
A cannon ball is shot into the air, moving upward at 70 meters per second. If the acceleration due to gravity is 10 m/s/s what is the velocity of the cannon ball (m/s) after three seconds?
40 m/s
A car moves with a constant velocity of 9 m/s toward the east for 5 seconds. The car moves
45
A 100 kg car is moving at 10 m/s. What is the car's kinetic energy?
5,000 J
A ball is dropped from an airplane at 10,000 ft with an initial velocity of 0 m/s. 5 seconds after it is dropped, what is the ball's downward velocity?
50 m/s
A sled is pulled 100 m across a snow slope. If the force required to do the pulling is 5 N, how much work was done to get the sled across?
500 J
Do 70 J of work in 10s and your power output is
7 W
You fire a cannon ball straight up, at 70 m/s. Disregarding air resistance, how long will it take the cannonball to reach maximum height, where it's velocity = 0 m/s?
7 s
Which of the two skydivers in the previous question, gets to the ground first?
A
Which of the following statements is true when terminal velocity is reached by a falling object?
Acceleration= 0 m/s/s forces are in equilibrium and net force = 0 N
Two skydivers jump at the same time from an airplane at 10,000 ft with an initial velocity of 0 m/s. Skydiver A is twice the mass of skydiver B and both have identical parachutes. Skydiver ________________ will reach terminal velocity first and skydiver ________________ will have the fastest terminal velocity.
B/A
An object falls freely from rest, off a cliff. Which of the following is true?
Kinetic energy is increasing as the object falls and Potential energy is decreasing as the object falls
When the cannon ball in the previous question reaches its maximum height, which of the following is true?
The cannon ball continues to experience force of gravity and is not in equilibrium
Energy can be transferred from one object to another. Also the form of energy can be changed from kinetic energy to potential energy or from potential energy to kinetic energy.
True
A bag of groceries has a mass of 25 kilograms and a weight of
about 25 N
A heavy object and a light object are dropped at the same time from rest in a vacuum. The heavier object reaches the ground
at the same as the lighter object
Chad and Emily are both captains of tug-of-war teams, at opposite ends of a rope. Chad's ream actually weighs more than Emily's team, but the rope is not moving. The question is not which team is stronger, but which team is exerting the greater force?
both exert equal force
A bird flies head-on into your car grill as you drive down the highway. Which experiences the greatest force?
both receive same force
Two cars are in a race. Car A moves only 1/3 as fast as car B. How does the kinetic energy of car A compare to that of car B?
car A has 1/9 x the KE of car B
A net force on an object produces
constant acceleration
The two factors that affect the force of resistance on the falling objects are _______________ and _______________.
cross sectional area and speed of the object
Kinetic energy is ______________ and potential energy is __________________.
energy of motion/ stored energy
A coconut and a smaller feather fall from a tree through the air to the ground below. The amount of air-resistance force is
greater on the coconut
An object following a straight-line path at constant speed
has 0 net force acting on it
As an object falls from 10,000 ft, each second it is falling air resistance is __________________ and the net force on the object is _____________________.
increasing/ decreasing
The work done by gravity on a bowling ball that rolls along a horizontal bowling alley
is 0 because the force of gravity is perpendicular to the ball's motion
Which of the following is not a step in the scientific method?
make an assumption
If you push for a half an hour, and then an hour against a stationary wall,
no work is done in either case
A wheel barrow is a ____________________ lever.
second class
Which of the following is not a vector quantity?
speed
Which task requires the most work; lifting a 30 kg sack 4 meters or lifting a 2 kg sack 50 meters?
the 30 kg sack
A light woman and a heavy man jump from an airplane at the same time and open their same size parachutes at the same time. Both reach a state of zero acceleration at different times. Who reaches zero acceleration first?
the light woman
The two measurements necessary for calculating average speed are
velocity and time
When a rock thrown straight upwards gets to the exact top of its path, its
velocity=0
If you do work on an object in 1/5th the usual time
your power is 5x the usual power output