Physical Science Study Guide

A 2-kg book is held 1 m above the floor for 50 s. The work done is

0(no work is done)

A centimeter is

0.01m

A car starts from rest and reaches a speed of 15 m/s in 10s. Its acceleration is

1.5 m/s squared

A total of 4900 J is expended in lifting a 50-kg mass. The mass is raised to a height of

10 m (w=4900 J) (m=50kg) (h=?) (h=w/mg=4900/(50)(9.80)=10m)

The KE of a 900-kg car who speed is 60 km/h is

125 kJ

A snail travels 45 cm in 20 min. It average speed is

135 cm/h

A person is 5 ft 8.0 tall. This is equivalent to

173 cm

A net force of 10 N gives an object an acceleration of 5 m/s squared. What net force would give the same object an acceleration of 1 m/s squared?

2 N

A 500 -g ball moves in a circle 40 cm in radius at a speed of 4 m/s. The centripetal force on the ball is

20 N

The mass of a sack of potatoes who weights is 200 N is

20.4 kg (n=200n)(m=?)(w=mg=>m=w/g=200n/9.80 m/s squared=20.4kg)

The linear momentum of a 400-kg giraffe galloping at 5 m/s is

2000 kgm/s

A moose weighting 3 kN is still standing still. The force the ground exerts on the moose is

3 kN

A stone dropped from a cliff reaches the ground in 4s. The stone's speed is then approximately.

40 m/s

When its brakes are applied, a car moving at 10 m/s undergoes an acceleration of -1.2 m/s squared. How far does the car travel before it comes to a stop?

42 m

A 50-kg person weighs

490 N (w=mg) (g=9.80 m/s squared) (m= 50 kg . 9.80 m/s squared= 490 N)

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

65 m

Six kJ of work is used to lift and object to a height of 100 m. The object's approximate mass is

6kg (w=6 kJ) (h=100m)(w=mgh)( m=w/gh, m=6000J/(9.80 m/s squared)(100m)=6000/980=6)

What distinguishes the scientific method from other ways of looking at the natural world is

Its reliance on experiment and observation

The scientist who showed that gravity accounts for Kepler's law of planetary motion was

Newton

In which one or more of the following is the earth assumed to be the center of the universe?

The Ptolemaic system

Why is the weight of an object greater at the poles than at the equator?

The poles are closer to the center of the earth (w=f=g m1.m2/r 2)

Which of the following quantities is always the same to all observers?

The speed of light.

The stars in a constellation

form a pattern in the sky as seen from the earth.

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.

When first proposed, a scientific idea is usually called a

hypothesis

A car who speed is a steady 50 km/h

is accelerated when it descends a hill, goes over the crest, and descends on the other side.

An object that has linear momentum must also have

kinetic energy.

If a spaceship 100 m long when at rest on the earth were to travel at nine-tenths the speed of light, its length is measured by and observer on the earth would be

less than 100 m.

In the formula E0= mc squared, the symbol c represents the speed of

light

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

one year

The watts is a unit of

power

A rocket is fired in space. As it moves, the total momentum of the rocket and its exhaust gases

remains the same.

The length of the year is

slightly more than 365 days.

What never changes when two or more objects collide is

the total momentum of all the objects.

An object moving in a circle at constant speed is accelerated

towards the center of the circle.

The British unit of length closest to the meter is the

yard