PHSC: CH 2

A massive block is being pulled along a horizontal frictionless surface by a constant horizontal force. The block must be __________.

moving with a constant nonzero acceleration

An object in motion tends to remain in motion

without the need of a force.

The net force on any object moving at constant velocity is

zero

When a rock thrown straight up reaches the exact top of its path, its velocity is

zero and its acceleration is 10 m/s2.

A tow truck exerts a force of 3000 N on a car that accelerates at 2 m/s2. The mass of the car must be

1500 kg

Which of Newton's laws focuses on inertia, which on acceleration, and which on action-reaction?

1st law- inertia 2nd law-acceleration 3rd law- action-reaction

A car has a mass of 1000 kg and accelerates at 2 m/s2. What is the magnitude of the force exerted on the car?

2000 N

A girl pulls on a 10-kg wagon with a constant force of 30 N. What is the wagon's acceleration?

3.0 m/s

A karate chop breaks a board with a blow of 3000 N. The force that acts on the hand during this event is

3000 N

If gravity between the Sun and Earth suddenly vanished, Earth would continue moving in

a straight-line path

If the mass of an object does not change, a constant net force on the object produces constant

acceleration

If the mass of an object does not change, a constant net force on the object produces constant

acceleration.

A block of mass 2kg is acted upon by two forces: 3N (directed to the left) and 4N (directed to the right). What can you say about the block's motion?

It could be moving to the left, moving to the right, or be instantaneously at rest.

Rank from greatest to least the weights of the 100-kg box of tools.

Jupiter, Earth, Moon

Consider a 100-kg box of tools in locations A, B, and C. Rank from greatest to least the masses of the 100-kg box of tools.

Jupiter= Earth= Moon

What is the net force acting on a 1-kg ball in free fall?

(1-kg)(9.8) = 9.8 N

Calculate the horizontal force that must be applied to a 1.1-kg puck to accelerate on a horizontal friction-free air table with the same acceleration it would have if it were dropped and fell freely.

(1.1-kg)(10)= F= 11 N

A rocket of mass 130000 kg undergoes an acceleration of 1.6 m/s2 Find the net force acting on it.

(13,0000 kg)(1.6 m/s^2)= Fnet= 208,0000

In the textbook acceleration is defined as a=Δv/Δt. Use this formula to find the acceleration of a cart on an inclined plane that gains 5.8 m/s each 0.90 s .

(5.8)m/s / (0.90) s = a= 6.4 m/s^2

If your mass is 74 kg , find your acceleration.

(50 N)(74 kg)= a= 0.68 m/s^2

A simple rearrangement of Newton's second law gives Fnet=ma. Find a net force that is needed to give a 8.0-kg package an acceleration of 8.0 m/s2 . (Note: The units kg⋅m/s2 and N are equivalent.).

(8.0 kg)(8.0 m/s^2)= Fnet= 64 N

What is the net force that acts on a 10-N falling object when it encounters 10 N of air resistance?

0 N

A 1-kg ball is thrown straight up at 10 m/s. Neglecting air resistance, the net force that acts on the ball when it is half way to the top of its path is

10 N

In the textbook we learn that the cause of acceleration is given by Newton's second law: a=Fnet/m. Find the acceleration that can result from a net force of 11 N exerted on a 2.2-kg cart. (Note: The unit N/kg is equivalent to m/s2.).

11 N / 2.2-kg = a= 5 m/s^2

An astronaut of mass 140 kg recedes from her spacecraft by activating a small propulsion unit attached to her back. The force generated by a spurt is 34 N Find her acceleration.

34 N/ 140 kg= a= 0.24 m/s^2

A person is attracted toward the center of Earth by a 500-N gravitational force. The force of attraction of Earth toward the person is

500 N

A 10-N falling object encounters 4 N of air resistance. The net force on it is

6 N

What is the net force that acts on a 10-N falling object when it encounters 4 N of air resistance?

6 N

From greatest to least, rank the accelerations of the boxes.

AC, DB

Boxes of various masses are on a friction-free level table. From greatest to least, rank the net forces on the boxes. A. 5N<5kg>10N B. 10N<10kg>15N C. 10N<5kg>15N D. 5N<20kg>15 N

D, ABC

If you stand next to a wall on a frictionless skateboard and push the wall with a force of 50 N , how hard does the wall push on you?

F= 50 N

An object cannot remain at rest unless which of the following holds?

The net force acting on it is zero

If a block is moving to the left at a constant velocity, what can one conclude?

The net force applied to the block is zero.

Is inertia a property of matter or a force of some kind?

a property of matter

A given net force propels an object along a straight-line path by a force. If the mass were doubled, its acceleration would

be half

Two forces, of magnitude 4N and 10N, are applied to an object. The relative direction of the forces is unknown. The net force acting on the object __________.

cannot have a magnitude equal to 5N

To steadily (constantly) increase the velocity of something requires a

constant force

A space probe in remote outer space continues moving

even though no force acts on it.

If an object's mass decreases while a constant force acts on it, the acceleration

increases

The force that directly propels a motor scooter along a highway is that provided by the

road