Test 4

A horizontal force of 5 N accelerates a 4 kg mass, from rest, at a rate of .5 m/s^2 in the positive direction. What friction force acts on the mass?

-3.0 N

1 kilogram = --- milligrams

1 million

If a net force accelerates a 4.5 kg tool at 40 m/s^2, what acceleration would that same net force give to an 18 kg tool?

10 m/s

If a falling objects gains 10 m/s each second it falls, its acceleration is

10 m/s^2

The mass of a lamb that weighs 110 N is about

11 kg

Starting from rest, a 4 kg body reaches a speed of 8 m/s in 2 seconds. What is the net force acting on the body?

16N

how much does a 3 kg bag of bolts weigh?

29.4 N

A 5 N force and a 30 N force act in the same direction on an object. What is the net force on the object?

35 N

Three forces all act on an object. The magnitudes are 80 N, 60 N, and 40 N. The resultant force acting on the object is given by

35.5 N at an angle of 34.3 degrees with respect to the x axis

You pull horizontally on a 50kg 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/s^2

An airplane increases its speed at the average rate of 15 mS^2. How much time does it take to increase its speed from 100 m/s to 160 m/s?

4 seconds

A 2 kg object moves with constant velocity 3 m/s toward the east. Two forces act on the object. The first is 40 N towards the west. Wha tis the second force that acts on the object ?

40 N east

A net force of 125 N is applied to a certain object. As a result, the object accelerates with an acceleration of 24 m/s^2. The mass is

5.21 kg

A late traveler rushes to catch a plane, pulling a suitcase with a force directed 30 degrees above the horizontal. If the applied force on the suitcase is 70 N , what is the horizontal component of the force exerted on the handle?

60.6 N

A truck is using a hook to tow a car whose mass is one quarter that of the truck. I fthe force exerted by the truck on the car is 6000 N, then the force exerted by the car on the truck is

6000 N

If I weigh 741 N on Earth at a place where g = 9.81 and 5320 N on the surface of another planet, what is the acceleration due to gravity on that planet?

70.4 m/s^2

If you are driving 72 km/h along a straight road and you look to the side for 4 seconds, how far do you travel during this time?

80 m

The acceleration due to gravity is lower on the moon than on earth. Which of the following statements is true about the mass and weight of an astronaut on the moon's surface, compared to earth?

Mass is the same ; weight is less

Suppose that an object is moving with a constant velocity. Which statement concerning its acceleration must be correct?

The acceleration is equal to zero

An object is moving with constant non-zero velocity. Which of the following statements must be true?

The net force on the object is zero

A 10 kg rock and a 20 kg rock are dropped at the same time and experience no significant air resistance. If the 10 kg rock falls with an acceleration a, what is the acceleration of the 29 kg rock?

a

The slope of a velocity versus time graph gives

acceleration

Human reaction time is usually greater than .10 seconds. If your friend holds a ruler between your fingers and releases it without warning, how far can you expect the ruler to fall before you catch it, neglecting air resistance?

at least 4.9 cm

If a nonzero net force is acting on an object, then the object is definitely

being accelerated

When the angle of an incline with a block resting on it increases, the normal support force

decreases

An object following a straight line path at a constant speed

has zero acceleration

Which of the following is the tendency of an object to maintain its state of motion?

intertia

The acceleration produced by a net force on an object is

inversely proportional to the mass, directly proportional to the net force, same direction of the net force

When a ball is thrown straight up with no air resistance, the acceleration at its highest point

is downward

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

it halves

SI unit for mass

kilogram

A measure of quantity for matter is

mass

in the absence of an external force, a moving object will

move with constant velocity in a straight line

Two cars collide head on. At every moment during the collision, the magnitude of the force of the first car exerts on the second is exactly equal to the magnitude of the force the second car exerts on the first. This is an example of

newtons third law

To push a piece of heavy furniture across the carpet usually takes more force to get it moving than it takes to keep it moving. This is because

static coefficient of friction is larger than the kinetic friction

A car goes forward along a level road at constant velocity. The additional force needed to bring the car into equilibrium is

zero

The amount of force needed to keep a .2 kg hockey puck moving at a constant speed of 7 m/s on frictionless ice is

zero