physical science Final Exam

Two 60-watt light bulbs are connected in parallel across a 120-V power line. The current in each bulb is

0.5 A.

The work you do in raising an orange from your waist to your mouth is roughly

1 J.

A 300-g ball is struck with a bat with a force of 150 N. If the bat was in contact with the ball for 0.02 s, the ball flew off at

10 m/s.

A car starts from a speed of 10 m/s with an acceleration of 2 m/s2. The time needed for the car to reach 30 m/s is

10 s.

The current in a 20-ohm electric heater operated at 240 V is

12 A.

A force of 2 N acts on a 2-kg object, initially at rest, for 2 s. During that time the object moves a distance of

2 m.

Two charges repel each other with a force of 10-6 N when they are 10 cm apart. When they are brought closer together until they are 2 cm apart, the force between them becomes

2.5 × 10-5 N.

A ship travels 20 km to the south and then 40 km to the west. The ship's displacement from its starting point is

45 km.

A 50-kg person weighs

490 N.

Which of the following sets of displacements might be able to return a car to its starting point?

60, 120, 180, and 240 km.

A car moving at 10 m/s undergoes an acceleration of 1.2 m/s2. In the next 5 s the car travels

65 m.

The specific heat of water is 4.2 kJ/kg°C. How long will it take for a 2-kW heating element to raise the temperature of 30 kg of water from 20°C to 80°C?

84 min

Relative to what she weighs on the earth, an astronaut visiting another planet

Any of these choices, depending on the planet.

The idea that all conclusions about the natural world must be based upon experiment and observation was first emphasized in the work of

Galileo

The wavelength of a sound wave is not related to its

amplitude.

If the moon were half as far from the earth as it is now, the gravitational force it exerts on the earth would be

four times its present value.

A stone is thrown upward from a roof at the same time as another, identical stone is dropped from there. The two stones

have the same acceleration when they reach the ground.

Coulomb's formula F = KQ1Q2/R2 gives the force between two charges in free space. The value of K

is the same under all circumstances.

When a liquid freezes to become a solid,

it gives off heat.

A bullet is fired upward. As it rises,

its mass remains the same while its weight decreases.

Matter waves are

never associated with stationary particles.

The period of the earth's orbit around the sun is

one year.

Light of which of the following colors has the longest wavelength?

red

Steam at 100°C is more dangerous than the same mass of water at 100°C because the steam

releases a great deal of heat when it condenses.

Sound waves of frequency 300 Hz have a speed relative to sound waves in the same medium of frequency 600 Hz that is

twice as great.