Chapter 10 Test ~ Science

In order to determine speed, you must know a. time b. distance c. both time and distance d. weight

c. both time and distance

During a race, a sprinter increases from 5.0 m/s to 7.5 m/s over a period of 1.25 s. What is the sprinters average acceleration during this period?

2 m/s2 change in velocity / by the change of time

A car moving at top speed of 20 m/s accelerates at a rate of -4 m/s2 to a complete stop. How long does it take the car to stop?

5s

If a car travels down the highway at a constant speed, are the forces acting on the car balances or unbalanced? Explain.

Balanced. If not so, then the car cannot move with uniform speed. The frictional force is balanced by the force exerted by the engine.

It is often recommended that motorists carry a heavy bag of sand in the trunk of their car when driving on slippery roads. Use the concept of friction to explain why this would be helpful.

This would be helpful because it would put more force onto the back of the car which creates more friction and that would help the car stop.

The difference between speed and velocity is that velocity includes a. direction b. distance c. time d. weight

a. direction

A car is parked on a hill. In order to keep the car from rolling downhill, how great must the static friction acting on the car be? a. equal to the force pulling the car downhill b. greater than the force pulling the car downhill c. greater than the force pulling the car uphill d. small than the force pulling the car uphill

a. equal to the force pulling the car downhill

Friction is defined as a. force that opposes motion between two surfaces that are touching b. rate at which velocity changes c. resistance of an object to a change in its velocity d. speed of an object in a particular direction

a. force that opposes motion between two surfaces that are touching

Which is an example of kinetic friction? a. friction between a car's windshield and the air as you drive into the wind b. friction between you and the ground as you stand still c. friction between a sticky note and a page of a book as it marks your place d. friction between your skin and a pencil as rests in your palm

a. friction between a car's windshield and the air as you drive into the wind

Which of the following statements are true? a. frictional forces are greatest when both surfaces are rough b. when a truck is parked on a hill, friction pulls the truck down the hill c. air resistance always opposes friction d. friction can exist between two objects even when they are not in contact

a. frictional forces are greatest when both surfaces are rough

Which of the following best illustrates unbalanced forces? a. a rock falling to the ground b. a stretched rubber band being held between two hands c. a person lifting a heavy box off of the ground d. a crash between a large truck and a train

b. a stretched rubber band being held between two hands

the distance traveled by an object divided by time it takes to travel that distance is called a. average velocity b. average speed c. average acceleration d. activity

b. average speed

If the net force action on a stationary object is zero, then the object will a. accelerate in the direction of the strongest force b. remain at rest c. begin moving backwards d. accelerate at a steady rate of speed

b. remain at rest

The SI unit for acceleration is a. mph b. ft/s2 c. m/s2 d. ^v/t

c. m/s2

How can the friction on a water slide be reduced? a. warm the surface of the slide b. keep the surface of the slide dry c. run a constant stream of water down the slide d. increase the slope of the slide

c. run a constant stream of water down the slide

Acceleration is defined as the change in velocity divided by a. speed b. final velocity c. time d. distance

c. time

Which of the following does NOT indicate velocity? a. 14 m/s SSE b. 40 km/h toward the town square along the main street c. 80 km/h going from New York toward New Jersey d. 28 km from Los Angeles to Catalina Island

d. 28 km from Los Angeles to Catalina Island

Which of the following is a displacement? a. 5 m/s b. 10ft c. -0.7 m/s2 d. 3 blocks east

d. 3 blocks east

An airplane is flying at 635 km per hour at an altitude of 35 000 m. It is currently over Kansas and is approximately 16 minutes ahead of its scheduled arrival time. What is its velocity? a. 635 km/h b. 16 m/min c. 35 000 m/s d. This cannot be determined without further information about its direction.

d. This cannot be determined without further information about its direction.

The combination of all of the forces acting on an object is called the a. total force b. union of forces c. super forces d. net force

d. net force

An object is in motion when a. you observe the object move b. the object's speed increases c. the object's displacement is greater than the distance traveled d. the object changes position relative to a stationary reference point

d. the object changes position relative to a stationary reference point

A tug-of-war that results in one team pulling the other across the line is an example of a. action forces b. reaction forces c. balanced forces d. unbalanced forces

d. unbalanced forces

a boat moves at a speed of 15 km/h in still water. The river it is traveling in flows at a rate of 3 km/h downstream. What is the velocity of the boat if it travels downstream? What is the velocity of the boat if it travels upstream?

If the boat travels downstream it would travel 18 km/h and if it traveled upstream it would travel 12 km/h.