Mastering Physics Chapter 4

the force of friction on a sliding object is 10N. the applied force needed to maintain the constant velocity is...

10N.

the mass of a lamb that weighs 110N is about...

11kg.

a tow truck exerts a force of 3000N on a car, which then accelerates at 2m/s^2. what is the mass of the car?

1500kg.

an apple at rest weighs 1N. the net force on the apple when it is in free fall is...

1N

the mass of a pet turtle that weighs 10N is about...

1kg.

a car has a mass of 1000kg and accelerates at 2m/s^2. what net force is exerted on the car?

2000N.

a 300-kg bear grasping a vertical tree slides down at constant velocity. the friction force between the tree and the bear is...

3000N.

a 500N parachutist opens his chute and experiences an air resistance force of 800N. the net force on the parachutist is then...

300N upward.

if you are driving at 20m/s and slam on your brakes and skid at 0.5g to a full stop the skidding time is about...

4 seconds.

a 10N falling objects encounters 10N of air resistance. the net force on the object is...

0N.

an apple weights 1N. when the apple is held at rest above your head, the net force on the apple is...

0N.

If a 50-N person is to fall at terminal speed, the air resistance needed is

50 N.

the human body can withstand an acceleration of 10g under certain conditions. what net force would produce this acceleration for a 50-kg person?

5000N.

phil stands at rest with both feet on a scale that reads 500N. when he gently lifts one food, the scale reads...

500N.

suzie skydiver, who weighs 500N, reaches terminal velocity of 90 km/h. the air resistance on suzie is then...

500N.

a 10-kilogram block with an initial velocity of 10m/s slides 10 meters across a horizontal surface and comes to rest. it takes the block 2 seconds to stop. the stopping force acting on the block is about...

50N.

a 10N falling object encounters 4N of air resistance. the net force on the object is...

6N.

if the mass of a cart is quickly loaded to have twice the mass while a propelling force remains constant, the cart's acceleration...

halves.

a light woman and a heavy man jump from an airplane with the same time and open their same size parachutes at the same time. which person will get to the ground first?

heavy man.

Consider a heavy and a light person jumping together with same-size parachutes from the same altitude. Who will reach the ground first?

heavy person.

a heavy rock and a light rock of the same size are falling through the air from a tall building. the one that encounters the greatest air resistance is the...

heavy rock.

when the bottom string is pulled slowly in the ehavy ball and string demonstration, tension...

in the top string is due to your pull plus the weight of the ball.

As the skydiver falls faster and faster through the air, air resistance

increases.

an object with twice as much mass as another object has twice as much...

inertia.

a skydiver steps from a helicopter and falls for a few seconds until terminal velocity is reached. thereafter until he opens his parachute, his acceleration...

is zero.

two tennis balls fall through the air from a tall building. one of them is filled with lead pellets. the ball to reach the ground first is the...

led filled.

When a 20-N falling object encounters 5 N of air resistance, its acceleration of fall is

less than g.

a ball is thrown vertically into the air. because of air resistance, its speed when it returns to its starting level compared with its inital speed is...

less.

a kilogram is a measure of an objects...

mass.

which has zero acceleration?

moving at constant velocity, mechanical equillibrium, at rest.

an object's weight is properly expressed in units of...

newtons.

compared to a 1-kg block of solid iron, a 2-kg block of iron has the same...

nothing.

a car by itself is capable of a certain maximum acceleration. when it tows a car of the same mass, its maximum acceleration is...

one half.

when you stand at rest with your left foot on one bathroom scale and your right foot on a similar scale, each of scales will..

show readings that when added equal your weight.

two factors that greatly affect air resistance on falling objects are frontal area and...

speed.

your weight as measured on your bathroom scale is..

the force due to gravity on you.

when a constant and sustained upward force acts on a rocket, its acceleration increases mainly because...

the mass of the rocket decreases as fuel is burned.

a rock weighs 30N on earth and another rock weights 30N on the moon. which has greater mass?

the one on the moon.

a feather and a coin will have equal accelerations when falling in a vacuum because...

the ratio of both the feather's and coin's weight to mass is the same.

a bowling ball and a baseball accelerate equally when falling in a vacuum because...

the ratio of their weights to mass is the same.

compared to the mass of an apple on earth, the mass of an apple on the moon is...

the same.

a heavy ball hangs by a string, with a second string attached to its bottom. a slow pull on the bottom string breaks...

the top string.

compared to a 1-kg block of solid iron, a 2-kg block of solid iron has twice as much...

volume, mass, inertia.

when a falling object has reached its terminal velocity, its acceleration is...

zero.

whenever the net force on an object is zero, its acceleration is...

zero.

a constant net force on a rail-road car produces constant...

acceleration.

if an apple experiences a constant net force, it will have a constant...

acceleration.

if you double the net force on an object, you'll double its...

acceleration.

which has the greater mass...

an automobile battery.

at equillibrium on a bathroom weighing scale, the downward pull of gravity on you is balanced by...

an upward support force.

A rock band's tour bus, mass (M), is accelerating away from a STOP sign at rate (a) when a piece of heavy metal, mass (M/6), falls onto the top of the bus and remains there. a. Show that the bus's acceleration is now 6/7a. b. If the initial acceleration of the bus is 1.2 m/s^2, show that when the bus carries the heavy metal with it, the acceleration will be 1.0m/s^2.

Initially: F = ma Finally: F = (m + m/6)a' Therefore: ma = (m + m/6)a' a = (7/6)a' (6/7)a = a' (6/7)(1.2) = 1.0 m/s²

a heavy ball hangs by a string, with a second string attatched to its bottom. a quick pull on the bottom string breaks the...

bottom string.

As the skydiver continues to fall faster and faster through the air, her acceleration

decreases.

As the skydiver continues to fall faster and faster through the air, net force

decreases.

suzie skydiver jumps from a high flying plane. as her velocity of fall increases, her acceleration...

decreases.

a newton is a unit of...

force.