Forces Motion And Energy: Chapter 2, Forces In Motion
Practice quiz for Holt Science and Technology: Forces Motion and Energy: Chapter 2, Forces in Motion
- 1.Which falls faster if there is no air resistance?
- A.
Heavier objects
- B.
Bigger objects
- C.
All ojects fall at the same speed
- 2.Who proved that objects of different mass fall at the same rate by dropping two cannonballs of different masses from the top of the leaning tower of Piza. The crowd was surprised to see that the two cannonballs reached the ground at the same time.
- A.
Newton
- B.
Galileo
- C.
Aristotle
- 3.All objects accellerate toward the earth at __________.
- A.
9.8 meters per second
- B.
8.9 Meters per second per second
- C.
9.8 meters per second per second
- 4.If there were no air, how fast would a ball be falling toward the earth after 10 seconds?
- A.
V = t - g so 10s - 9.8m/s/s = .2 m/s
- B.
V = t /g so 10s/9.8m/s/s = 1.02 m/s
- C.
V = t x g so 10s x 9.8m/s/s = 98 m/s
- 5.If you were to drop a feather and a marble right now, the marble will fall fall faster. Why?
- A.
Air resistance
- B.
The marble is heavier
- C.
The feather is from a bird and birds fly
- 6.Air resistance is a kind of _______.
- A.
Sliding friction
- B.
Fluid friction
- C.
Rolling friction
- 7.How would you calculate the force acting on a falling object?
- A.
The force of gravity multiplied by the force of air resistance
- B.
The force of gravity divided by the force of air resistance
- C.
The force of gravity minus the force of air resistance
- 8.define terminatl velocity
- A.
When something falls at a constant rate because the downward force of gravity equals the upward force of air resistance
- B.
the velocity of a train as it passes the terminal
- C.
The velocity of an object after it has come to rest on the ground
- 9.What two factors determine the amount of air resistance.
- A.
Size and mass
- B.
Shape and mass
- C.
Size and shape
- 10.Why does an astronaut appear to loat inside the spacecraft?
- A.
The astronaut is weightless
- B.
Both the astronaut and the spacecraft are in free fall.
- C.
They are in outer space where there is no gravity
- 11.Define free fall.
- A.
When gravity is pulling an object down and no other forces are acting on it.
- B.
When something is falling out of an airplane
- C.
When something is falling, but it is weightless
- 12.define orbit.
- A.
When something is travelling in a straight path
- B.
When something is traveling in a curved path
- C.
When something is travelling in a circular or near circular path around something else.
- 13.What two motions combine to cause one object to orbit another?
- A.
Constant forward motion and free fall
- B.
Constant circular motion and free fall
- C.
Constant forward motion and constant circular motion
- 14.Define projectile motion.
- A.
When something is travelling in a circular or near circular path around something else.
- B.
The vibration of a projectile
- C.
The curved path an oject follows when it is thrown or propelled near the surface of the earth.
- 15.Projectile motion results from combining two motions. What are they?
- A.
Accelerating horizontal motion and constant vertical motion
- B.
Constant horizontal motion and vertical motion accelerating because of gravity
- C.
Free fall and accelerating horizontal motion
- 16.Which law is this: The accelleration of an object depends on the mass of the object and the force applied.
- A.
Newtons First Law of motion
- B.
Newton's second law of motion
- C.
Newton's third law of motion
- 17.Which law is this: Whenever one object exerts a force on a second object, the second object exerts an equal and opposite force on the first.
- A.
Newtons First law of motion
- B.
Newton's second law of motion
- C.
Newton's third law of motion
- 18.How does a rocket engine work and which of Newton's laws of motion is involved.
- A.
The rocket engine pushes gases downward so the gases push the rocket upward with an equal force. Newton's Third Law
- B.
The gases flying out of the rocket engine push against the ground. Newton's Second law.
- C.
Heat rises. Newton's First Law.
- 19.Which Law is this: An object at rest remains at rest and an object in motion remains in motion at a constant speed and in a straight line unless acted upon by an unbalanced force.
- A.
Newton's first law of motion
- B.
Newton's second law of Motion
- C.
Newton's third law of motion
- 20.If you were to throw a ball right now, why wouldn't it travel in a straight line forever?
- A.
Because unbalanced forces act on it.
- B.
Because of gravity and air resistance.
- C.
All of the above. Gravity and air resistance provide the unbalanced forces.
- 21.Define inertia.
- A.
The tendancy of all objects to resist any change in motion.
- B.
Change in speed over a period of time.
- 22.Between two objects, which will have more inertia?
- A.
The one with less mass
- B.
The one that is traveling faster
- C.
The one with more mass
- 23.What determines how much an object will accellerate?
- A.
The amount of force acting on the object
- B.
The mass of the object
- C.
Both the mass of the object and the force acting on it
- 24.How do you state Newton's second law mathematically? (a = accelleration; m = mass; f = force)
- A.
A = f x m
- B.
A = f / m
- C.
A = f + m
- D.
A = f - m
- 25.What is a second way of stating newton's second law mathematically?
- A.
F = m x a
- B.
F = m - a
- C.
F = m / a
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