Physics test Flashcards
The rate at which an object moves is _____.
Speed
The rate at which velocity changes is ____________.
Acceleration
The fulcrum is between the input force and the load
First-Class Lever
The speed of an object in a particular direction is ________.
Velocity
When combining velocities that are going in opposite directions we
Subtract the smaller velocity from the larger one
What is the graph describing
Positive acceleration
A vehicle travels 3,000m in 250s toward the evening sun. What is its velocity?
12 m/s west
The tendency for all objects to resist a change in motion
Inertia
What is the acceleration of a car that goes from 50 m/s north to 75 m/s north in 5s?
5 m/s² north
What is the acceleration of a bike that goes from 64 m/s east to a stop in 4s?
-16 m/s² east
In 0.6 seconds, a projectile goes from 0 to 360 m/s south. What is the acceleration of the projectile?
600 m/s² south
A number that tells how many times a machine multiplies force.
Mechanical Advantage
If a car’s average speed is 30 km/hr, how far can it travel in 2 hours?
60km
The work output for a machine is always less than the work input because
of the effect of friction
A machine can increase _.
D
Which of the following statements about machines is true?
D
A comparison of a machine’s work output with the work input.
Mechanical efficiency
If you use a machine to increase the output force, what must also be true?
The distance over which the force is applied must increase.
Which of the following things is an example of a lever?
A DoorKnob
A property of moving objects that depends on the object’s mass and velocity.
Momentum
A wheelchair ramp on a building is an example of what type of simple machine?
Inclined Plane
A single fixed pulley will..
Change the direction of the force
What is the mechanical advantage of an inclined plane 6m long and .5m high?
12
What is the mechanical advantage of a wheel and axle with a wheel radius of 48cm and an axle diameter of 4cm?
24
The acceleration of an object depends on the mass of the object and the amount of force applied.
Newton’s 2nd law of motion
The load is between the fulcrum and the input force.
Second-Class Lever
What is a measure of gravitational force called?
Weight
A mechanical advantage greater than one means..
The outer force is greater than the input force
What is the velocity of a stone dropped from a cliff that takes 6 seconds to hit the ground?
58.8 m/s south
A ball falls from a balcony and hits the ground with a velocity of 78.4 m/s down. How long does the ball fall?
8 seconds
Fluid friction
The constant velocity at which a falling object travels when the air resistance matches the force of gravity is called ________ ________.
Terminal Velocity
An object at rest tends to stay at rest and an object in motion tends to stay in motion.
Newtons 1st Law of Motion
Projectile motion is __________
The curved path of an object follows when thrown or propelled near the surface of the earth
The input force is between the fulcrum and the load.
3rd Class-Lever
Objects of different masses will fall at the same rate in a vacuum because of _______
Inertia
For every action, there is an equal and opposite reaction is _______ ___ ___ __ ______.
Newtons 3rd law of Motion
What force is necessary to accelerate a 1000kg box at a rate of 20 m/s/s?
20,000N
What is the momentum of a 70kg athlete running 10 m/s?
700 kg m/s
A change in pressure at any one point in an enclosed fluid will be transmitted equally to all parts of that fluid.
Pascals Principle
Fluids floww…
to areas of higher pressure, i think
Find the weight of a rock with an area of 2m² that exerts a pressure of 64 Pa.
128N
Find the pressure exerted by a 3,600 N box with an area of 9m².
400 Pa
The buoyant force on an object in a fluid is an upward force equal to the weight of the volume of fluid that the object displaces.
Archimedes Principle
As the speed of a moving fluid increases, its pressure decreases.
Bernoulli’s Principle
The upward force of an object is caused by pressure differences.
Lift
Planes with small wings need ____ ______
More Thrust
An object will float if…
The buoyant force is equal to or greater than its weight
When the buoyant force is greater than the object’s weight, the object will
Float
Force is measured in __________
Newtons
A push or a pull is A _____
Force
What is the force of an object that is 25N up and 15N down?
10N
All force has ____ and _________
Size and Direction
An object will move when the force is __________.
Unbalanced
Friction occurs when
All of the Above
Rolling friction is..
The force that opposes the motion of objects moving across a surface on wheels, less than sliding friction.
Friction can be increased by _________ ___ ______ _____ ________ _______.
Increasing the normal force between objects.
Increasing the amount of surface contact between two objects will ________ ___ __________ _____..
Increase the frictional force
Fluid between two surfaces will ______ _______.
Reduce Friction
A man applies a force of 250N to push a box across the floor 5m. How much work does he do?
1250 Joules
You lift a chair that weighs 60N to a height of 3m and carry it 5m across the room. How much work do you do on the chair?
180 Joules
What is the power of a small motor that can do 2000 Joules of work in 20 seconds
100W
How far was an 80N box pushed if 320 J of work was done?
4m
In which situation do you do more work?
u better hope Chiara has Gauth AI lil bro
Power is…
The rate at which work is done.
Work is being done when
You exert a force that moves an object in the direction of the force.
You and a friend together apply a force of 500N to a 1,000N car to make it roll 5m in 1 minute and 40 seconds. How much work did you and your friend do combined
2500 Joules
You and a friend together apply a force of 500N to a 1,000N car to make it roll 5m in 1 minute and 40 seconds. What was your combined power?
25 Watts
You apply 25N to a machine, and the machine applies 2,500N to an object. What is the mechanical advantage?
100
What is the force of attraction between objects due to their masses?
Gravity
