Newton's Laws
Newton's Law
Gravity, Energy, and Forces
Machines
Problems
100
In what circumstances would an object maintain a constant velocity? A) when the object has no inertia B) when the object experiences no friction C) when there is no net force acting on the object D) when the forces acting on an object remain constant
What is D) when the forces acting on an object remain constant
100
The law that states that the unbalanced force acting on an object equals the object's mass times it's acceleration is A) Newton's first law of motion. B) Newton's second law of motion. C) Newton's third law of motion. D) the law of conservation of momentum.
What is B) Newton's second law of motion.
100
The law of conservation of energy states that A) the energy of a system can disappear. B) it is impossible to make a perpetual motion machine. C) energy cannot change form. D) energy can neither be created or destroyed.
What is D) energy can neither be created or destroyed.
100
Which of the following is a compound machine? A) a wheel and axle B) a pulley C) a pair of pliers D) a ramp
What is C) a pair of pliers
100
A car travels east with a velocity of 25 m/s. The wind also blows to the east with a velocity of 7m/s. What is the resultant velocity of the plane? A) 175 m/s B) 18 m/s C) 3.5 m/s D)32 m/s
What is D) 32 m/s
200
A girl is pulling a wagon that holds her baby brother. If she pulls with a constant velocity, which statement is true? A) The wagon is pulling on the girl with the same force that she is pulling on it. B) The force her baby brother exerts on the wagon is greater than the force the wagon exerts on him. C) The girl is able to make the wagon move because she is pulling harder on the wagon than the wagon is pulling on her. D) The force the girl exerts on the wagon is equal to the force the wagon exerts against the ground.
What is A) The wagon is pulling on the girl with the same force that she is pulling on it.
200
A motorcycle and a van collide into each other while traveling the same speed. Upon impact, the motorcycle flies away from the van before crashing to the ground, while the van barely moves in comparison. What best describes how the forces the two vehicles exert on each other compare? A) The force the motorcycle exerts on the van is greater. B) The force the van exerts on the motorcycle is slightly greater. C) The force the van exerts on the motorcycle is much greater. D) The forces the vehicles exert on each other are equal and opposite.
What is D) The forces the vehicles exert on each other are equal and opposite.
200
What happens in a coal-burning power plant as energy is transferred from coal to produce electricity? A) The system tends toward equilibrium, resulting in a decrease in entropy. B) The more electricity the plant produces, the more the energy in the system increases. C) The transfer of energy from coal to electricity causes some of the energy to be destroyed. D) The energy available for work decreases as some of the coal is transformed into ash and combustion gases.
What is D) The energy available for work decreases as some of the coal is transformed into ash and combustion gases.
200
An inclined plane A) changes the direction of the force only. B) changes the magnitude of the force only. C) changes both the magnitude and the direction of the force. D) decreases the amount of work.
What is C) changes both the magnitude and the direction of the force.
200
A 22-kilogram wagon is accelerating at a rate of 2 m/s2 westward. What is the net force acting upon the wagon? A) 0.09 newtons west B) 11 newtons west C) 20 newtons west D) 44 newtons west
What is D) 44 newtons west 2nd Law Force = (mass) (acceleration)
300
Which of the following is the best example of Newton's first law? A) A planet's orbit is dependent upon its mass and distance from the sun. B) A soccer ball remains motionless on the ground until it is kicked. C) When two cars collide, they exert equal and opposite forces on each other. D) A falling rock's acceleration is dependent upon gravity and wind resistance.
What is B) A soccer ball remains motionless on the ground until it is kicked. An object at rest will remain at rest. (1st Law)
300
The combination of all of the forces acting on an object is called the A) total force. B) union of forces. C) super force. D) net force.
What is D) net force.
300
When air resistance balances the weight of an object that is falling, the velocity A) slowly decreases. B) remains constant. C) rapidly increases. D) None of the above.
What is B) remains constant.
300
A machine is a device that A) requires less work to do a given task. B) decreases the amount of work done by a given force. C) increases energy. D) can multiply and change the direction of an input force.
What is D) can multiply and change the direction of an input force.
300
A girl kicks a ball eastward with a force of 8 newtons. The ball's mass is 0.4 kilograms. At what rate is the ball accelerating? A) 3.2 m/s2 B) 5 m/s2 C) 20 m/s2 D) 32 m/s2
What is C) 20 m/s2
400
A person leans against a wall, and the wall exerts an equal and opposite force on the person. Which of Newton's laws does this example best illustrate? A) third law of motion B) law of inertia C) second law of motion D) law of universal gravitation
What is A) third law of motion
400
A boy jumped off of his skateboard, and the skateboard rolled backwards. Whatbest explains why the skateboard rolled backwards? A) because the force the boy exerted on the skateboard caused the skateboard to change its velocity B) because the force the boy exerted on the skateboard was opposite in direction of the force the skateboard exerted on the boy C) because the force the boy exerted on the skateboard caused the skateboard to push down against the ground D) because the force the boy exerted on the skateboard was opposite in direction of the force the ground exerted against the skateboard
What is A) because the force the boy exerted on the skateboard caused the skateboard to change its velocity
400
What will happen to the gravitational force between two objects if the mass of one of the objects doubles? A) The gravitational force will become a quarter as great. B) The gravitational force will become half as great. C) The gravitational force will become two times as great. D) The gravitational force will become three times as great.
What is C) The gravitational force will become two times as great.
400
How can the efficiency of a ramp be increased? A) increase its length. B) decrease its length. C) make the surface of the ramp smoother. D) use more force to move the object up the ramp.
What is C) make the surface of the ramp smoother.
400
An object has a kinetic energy of 810 J after falling a certain distance. If the mass of the object is 20 kg, what is the speed of the objects at this time? A) Cannot be determined B) 9 m/s C) 8 m/s D) 7 m/s
What is B) 9 m/s
500
The picture on the board shows a pendulum at three different positions as it swings back and forth. Assume the pendulum is in motion and does NOT experience ANY friction or air resistance. The potential energy of the pendulum at position X is 20 J. Use the Law of Conservation of Energy to explain changes in both kinetic AND potential energy as the pendulum moves from position X to position Y, and from position Y to position Z.
What is Kinetic energy increases and potential energy decreases between x and y. At point y potential energy is zero joules and kinetic energy has now reached 10 joules. Between y and z kinetic energy decreases and potential energy increases. At point z, kinetic energy is 0 joules and potential energy is at 10 joules again.
500
Which of the following best describes Newton's first law? A) If there are external unbalanced forces acting upon an object, the object will remain motionless. B) The force of attraction between two objects is dependent upon the objects' masses and the distance between them. C) If all the external forces acting on an object cancel each other out, the object will remain in its state of motion. D) If one object exerts a force on a second object, the second object exerts an equal and opposite force on the first object.
What is C) If all the external forces acting on an object cancel each other out, the object will remain in its state of motion.
500
What will happen to the gravitational force between two objects if the distance between them is decreased 50%? A) The gravitational force will become two times as great. B) The gravitational force will become four times as great. C) The gravitational force will become eight times as great. D) The gravitational force will become sixteen times as great.
What is B) The gravitational force will become four times as great.
500
A boy pushes on a parked car with a force of 200 N. The car does not move. How much work is done does the boy do on the car? A) 200 N B) 200 j C) Zero D) Cannot be determined
What is C) Zero
500
A medicine ball has a mass of 5 kg and is thrown with a speed of 2 m/s. What is its kinetic energy? A) 100 J B) 10 J C) 2000 J D) 500 J
What is B) 10 J
M
e
n
u