SCIENCE 1st QUARTER EXAM

Usable chemical energy in food begins as __________ energy. A) heat B) sound C) light D) mechanical motion

Light

Is a car slowing at a traffic light an example of balanced or unbalanced forces?

UNbalanced-

What is the resultant force on the box? PUT on board

0 Net Force. They cancel each other out

A car jack allows you to lift up a heavy car. The car jack works because A) you apply a greater force over a longer distance. B) you apply a smaller force over a longer distance. C) you apply a greater force over a shorter distance. D) you apply a smaller force over a shorter distance.

B

You throw a rock off the top of a mountain. In terms of energy, what best describes what happens? 1. kinetic energy increases, so does the total energy 2. potential energy decreases, total energy decreases 3. Both the kinetic and potential energy changed, but the TOTAL energy remains constant

3. According to Newton's Law of Conservation of energy energy: energy cannot be created or destryed in a system. It can only be transformed.

How does a single fixed pulley, like the one seen here, help you do work? A) changes the direction of the force B) increases the amount of applied force C) decreases the amount of applied force D) allows you to pull the rope a shorter distance

A. Changes the direction of the force

What is a good example of Inertia? A. a car sitting motionless on a driveway B. a ball returns to your hand after you throw it up in the air C. a ball gathers speed as it rolls downhill

A. It resists movement unless a force acts on it

Which of these would have the greatest potential energy? A) A roller coaster at the top of a hill. B) A roller coaster half-way up the hill. C) A roller coaster half-way down the hill. D) A roller coaster at the bottom of the hill.

A. The coaster at the top of the hill

A solar powered car converts _______________ energy into _________________ energy. A) light, chemical B) light, mechanical C) mechanical, light D) electrical, mechanical

B light, Mechanical

Is the velocity changing? 1. Car going down straight track at 30 m/s 2. Car going around a circular track at 30 m/s 3. The car goes from 0 m/s to 20 m/s

B. Because the DIRECTION is changing as the car moves in a circular motion

Heat is transferred from the heating element to the pot to the boiling water. What is the MOST likely method of heat transfer? A) circulation B) conduction C) convection D) radiation

B. Conduction

James and Juan were at the highest point in the football stadium, dropping water balloons on people below. Many of the balloons did not break, so the boys added more water to the balloons. What impact did adding water have on the balloons' potential energy? A) It had no impact; it just made the balloons bigger. B) The gravitational potential energy increased because the mass increased. C) The gravitational potential energy decreased because the diameter increased. D) The gravitational potential energy remained constant because they did not increase the height. 54)

B. Gravitational energy increased because mass increased

A solar powered car converts _______________ energy into _________________ energy. A) light, chemical B) light, mechanical C) mechanical, light D) electrical, mechanical

B. Light into mechanical energy

How can you decrease the effort force needed to push a weight to the top of the ramp? A) cover the surface with carpet B) increase the length of the ramp C) increase the height of the ramp D) decrease the length of the ramp

B. increase the length of the ramp

Which of the following factors will LEAST effect the force of gravity between the earth and the elephant? A. an elephant flying to the moon B. an elephant eating 200 lbs of food C. an elephant walking across flat land

C. Because neither the elephant's mass nor distance from the Earths core changes

Warm air rises at the equator and cold AIR sinks at the poles creating A) tornadoes. B) hurricanes. C) convection currents. D) the Coriolis effect.

C. Convection

Warm air rises at the equator and cold air sinks at the poles creating A) tornadoes. B) hurricanes. C) convection currents. D) the Coriolis effect.

C. Convection currents

The law of conservation of energy states that A) energy may be created, destroyed or transformed. B) energy may be created, but only in certain types of nuclear reactions. C) energy may neither be created nor destroyed; it may only be transformed. D) the energy created by one process must be equal to that destroyed by another process.

C. It cannot be created or destroyed. It can only be transformed.

What is the main method of heat transfer from the core to the crust of the earth?

Convection

What type of currents are responsible for circulating hot and cold AIR in the atmosphere and causing local weather systems?

Convection

8) During the day, the temperature of the sand in a desert rises as the sand is heated by the sun. After the sun sets, the sand cools. What happens to the heat energy in the sand as it cools? A) It is destroyed. B) It is used by the sand to do work. C) It goes back into the sun, completing the cycle. D) It is transferred to the air via the process of radiation.

D. It is transferred to the Air by the process of radiation

If the force of gravity between the sun and the planets disappeared, what would happen to the path the planets follow? A) They would continue to rotate around the sun. B) The planets velocity would increase as it got closer to the sun. C) The speed at which they are moving would significantly slow down. D) They would move in a straight line at a constant speed and velocity.

D. It would move in a straight line at a constant speed.

An example of mechanical energy being converted into heat energy is A) the sun. B) a generator. C) a Snickers bar. D) rubbing your hands together.

D. Rubbing hands together

) An example of mechanical energy being converted into heat energy is A) the sun. B) a generator. C) a Snickers bar. D) rubbing your hands together.

D. Rubbing your hands together

A generator converts mechanical energy into _____________________ energy. A) chemical B) electrical C) light D) sound

Electrical

What is the law of conservation of energy?

Energy cannot be created or destroyed in a system. The total amount of energy stays the same.

The tendency of two masses alone in the universe to drift together is a result of A) fission. B) friction. C) fusion. D) gravity.

Gravity

You throw a tennis ball in a straight path, what 2 forces cause the ball to eventually stop moving?

Gravity and friction (wind resistance)

Energy is added in the form of heat to a pot of water on the stove. This causes the water to A) decrease kinetic energy. B) increase kinetic energy. C) decrease potential energy. D) increase potential energy.

Increase kinetic energy. The molecules in the water are moving faster.

What is Newton's first law ?

Inertia

What happens to any object that falls from an airplane? 1. Accelerates 2. Falls at constant rate of speed 3. It accelerates until it reaches peak velocity, then decelerates

It accelerates. According to the Law of Gravity

When energy is used to rotate the sails of a windmill--what type of energy do the sails have? 1. potential 2. kinetic 3. heat 4. electromagnetic

Kinetic (moving)

Your hands get warm by a fire because ________________energy is converted into heat energy. A) chemical B) electrical C) mechanical D) nuclear

Mechanical

Which planet has the GREATEST attraction to the sun? A) Mars B) Pluto C) Saturn D) Mercury

Mercury. It is closest to the sun.

Two people are pushing against a file cabinet with the same force of 15 Newtons. What happens to the box? Does the box move?

No, because the forces cancel each other out. The box doesn't move.

Is a car moving at a constant speed of 60mph accelerating?

No. Acceleration involves a change in speed or direction.

What type of heat transfer occurs when the sun warms the earth?

Radiation The sun radiates heat to warm the earth

What happens when a gas engine transform 1/2 of its chemical energy into mechanical? If energy is conserved, what happens to the other 1/2 of the energy? What energy is it transformed into?

Remember that total energy cannot be lost or gained. It is transformed into Thermal energy

When you turn on your TV electrical energy is transformed into other forms of energy. Name three.

Sound, heat, light

Which machine is a lever? Saw, stapler, hammer, ramp

Stapler

A 10.00 kilogram mass of iron on earth exerts a downward force of 258 Newtons. On the moon the same mass of iron exerts a downward force of 63 Newtons. Why?

The gravity of the moon is 1/6 the gravity of earth

Three zebras step on a scale at the zoo. Zebra A weighs 250 lbs; zebra b weighs 350 lbs, and zebra C weighs 258 lbs. Which one would experience the greatest force due to gravity?

The heaviest animal. Weight if the measurement of the force of gravity on an object. The greater the weight, the greater the gravity.

Why is gravity on the moon 1/6th the gravity on earth?

The moon is much less massive than the earth

Conduction occurs more easily between solids and liquids. Why does it not occur easily in gases?

The particles of gases are further apart and move faster

What is the main source of energy for our planet?

The sun

What do a nuclear plant, a hydroelectric dam and a coal burning power plant have in common?

They are all sources of electricity. They all transform one type of energy into electricity.

) Which of these would have the greatest potential energy? A) A roller coaster at the top of a hill. B) A roller coaster half-way up the hill. C) A roller coaster half-way down the hill

Top of the hill

Is a car going around a curve at a constant speed accelerating?

Yes, An accelerating object is an object that is changing its velocity. And since velocity is a vector that has both magnitude and DIRECTION , a change in either the magnitude or the direction constitutes a change in the velocity

What is the primary mechanical advantage of using a lever?

You apply a small input force and have it multiplied into a large output source

What is the primary mechanical advantage of using a screw?

You apply a small input force to penetrate something that normally requires a large force.

A microwave converts ______energy into ______ energy.

electrical into electromagnetic

As a roller coaster goes down hill (potential/electric) energy is converted to kinetic/mechanical) energy.

potential energy (stored) is converted to kinetic energy (moving)