Macro final

A book weighs 4 N. When held at rest in your hands, the net force on the book is

0 N

a ball is thrown straight up. At the top of its path its instantaneous speed is

0 m/s

A train travels 6 meters in the first second of travel, 6 meters again during the second second of travel, and 6 meters again during the third second. Its acceleration is

0 m/s2

A projectile launched horizontally hits the ground in 0.8 seconds. If it had been launched with a much higher speed in the same direction, it would have hit the ground (neglecting Earth's curvature and air resistance) in

0.8s

An apple weighs 1 N. The net force on the apple when it is in free fall is

1 N

a certain unbalanced force gives a 20 kg object an acceleration of 2 m/s2. what acceleration would the same force give a 30 kg object?

1.3 m/s2

a bicycle 15 km in 30 minutes

1/2 km/hr

If a freely falling object were somehow equipped with a speedometer, its speed reading would increase each second by

10 m/s

a ball is thrown straight up. At the top of its acceleration is

10 m/s2

when something falls to the ground it accelerates. This acceleration is called the acceleration due to gravity and is symbolized by letter g. what is g

10 m/s2

A car accelerates at 2 meters/s/s. Assuming the car starts from rest, how much time does it need to accelerate to a speed of 20 m/s

10 seconds

suppose the force of friction on a sliding object is 25 N. The force needed to maintain a constant velocity is

25 N

If you pull horizontally on a desk with a force of 150 N and the desk doesn't move, the friction force must be 150 N. Now if you pull with 250 N so the desk slides at constant velocity, the friction force is

250 N

starting from rest, a car undergoes a constant ace of 6 m/s2/ how far will travel in first second

3 m

a skateboarder accelerates 2m/s for 2 s

4 m/s

You pull horizontally on a 50 kg crate with a force of 450 N and the friction force on the crate is 250 N. The acceleration of the crate is

4 m/s2

suppose that you exert 300 N horizontally on a 50 kg crate on a factory floor, where friction between the crate is 100 N. What is the acceleration of the crate?

4 m/s2

Suppose a car is moving in a straight line and steadily increases its speed. It moves from 35 km/h to 40 km/h the first second and from 40 km/h to 45 km/h the next second. What is the car's acceleration?

5 km/hr

an apple

5 m/s

a package falls out of a helicopter that is traveling horizontally at 70 m/s. It falls into the water below 8 seconds later. Assuming no air resistance, what is the horizontal distance it travels while falling

560m

a car starts from rest and after 7 seconds it is moving at 42 m/s. what is the car's average acceleration?

6 m/s2

If a projectile is fired straight up at a speed of 30 m/s, the total time to return to its starting point is about

6 seconds

Suppose you take a trip that covers 180 km and takes 3 hours to make. Your average speed is

60 km/h

A freely falling object starts from rest. After falling for 6 seconds, it will have a speed of about

60 m/s

how much time does a car with an acceleration of 5 m/s2 take to go from 5- 40 m/s

7 s

average acceleration of a car that goes from rest to 60 km/h in 8 seconds

7.5 km/hr

how much force is needed to accelerate a 4 kg physics book to an acceleration of 2 m/s2

8 N

a scalar is a quantity that has

magnitude

a vector is a quantity that has

magnitude and direction

At the instant a ball is thrown horizontally with a large force, an identical ball is dropped from the same height. Which ball hits the ground first?

neither

If you drop a feather and a coin at the same time in a vacuum tube, which will reach the bottom of the tube first?

neither

acceleration is defined as

the rate at which velocity itself changes

If you drop a feather and a coin at the same time in a tube filled with air, which will reach the bottom of the tube first?

coin

a force of 3 N accelerates a mass of 3 kg at the rate of 1 m/s2. The acceleration of a mass of 6 kg acted upon by a force of 6 N is the same.

the same

a ball is thrown upwards and caught when it comes back down. In the absence of air resistance, the speed the ball when caught would be

the same as the speed it had when thrown upwards

In the absence of air friction, the horizontal component of a projectile's velocity doesn't change as the projectile moves.

always true

accelerations are produced by

forces

Consider drops of water leaking from a water faucet. As the drops fall they

get farther apart

When you look at the speedometer in a moving car, you can see the car's

instantaneous speed

Suppose a cart is being moved by a force. If suddenly a load is dumped into the cart so that the cart's mass doubles, what happens to the cart's acceleration?

it halves

speed is

all of the above

a box is dragged without acceleration in a straight line path across a level surface by a force of 13 N. What is the frictional force between the box and the surface?

13 N

a stone is dropped from a cliff. After it has fallen 10m, what is the stones velocity?

14 m/s

A crate falls from an airplane flying horizontally at an altitude of 1250 m. Neglecting air drag, how long will the crate take to strike the ground?

15.8 s

a 20 N falling object encounters 4 N of Air resistance. The magnitude of the net force on the object is

16 N

average speed of cheetah that runs 88 m in 5 seconds

17.6 m/s

a net force of 1 N acts on a 4 kg object. Initially at rest, for 4 seconds. what is the distance the object moves during that time?

2 m

A girl pulls on a 10-kg wagon with a constant force of 20 N. What is the wagon's acceleration?

2 m/s2

a jet has a mass of 40,000 kg. the thrust for each of four engines is 20,000 N. What is the jet's acceleration taking off?

2 m/s2

you push with 10 N on a 5 kg block and there are no opposing forces. How fast will the block accelerate?

2 m/s2

toss boll straight up so it takes 4 s to return

20 m/s

a tow truck exerts a force of 2000 N on a car, accelerating it at 1 m/s/s. what is the mass

2000 kg

If a ball were equipped with a speedometer and allowed to fall freely on a planet where the acceleration due to gravity is 23 m/s2, the reading on the speedometer would increase each second by

23 m/s

Suppose an object is in free fall. Each second the object falls

a larger distance than in the second before

An object has a constant mass. A constant force on the object produces constant

acceleration

In the absence of air resistance, objects fall at constant

acceleration

The acceleration produced by a net force on an object is

all of the above

When representing velocity as a vector

all of the above

a ball tossed vertically upwards rises, reaches its highest point, and then falls back to its starting point. During this time the acceleration of the ball is always

directed downward

acceleration is defined as the change in

velocity divided by the time interval

As an object falls freely in a vacuum, its

velocity increases

a push on a 1 kilogram brick accelerates the brick. Neglecting friction, to equally accelerate a 10 kilo brick, one would have to push

with 10 times as much force

suppose you are in a car that is going around a curve. The speedometer reads a constant 30 mph. which of the following is not true?

your velocity is constant