Work and Kinetic Energy

Question 1

Quantity that can be converted from one form to another; involved in all interactions leading to changes in state (phase changes or changes in state of motion); a scalar quantity

Answer 1

Energy

Question 2

SI Unit of energy

Answer 2

Joule

Question 3

Two types of mechanical energy

Answer 3

Kinetic and Potential

Question 4

Energy that objects possess due to their motion

Answer 4

Kinetic Energy

Question 5

Formula for Kinetic Energy

Answer 5

K=1/2mv^2 (where m is mass, and v is speed)

Question 6

Energy transferred to the object via the application of force along a displacement; energy in motion; scalar quantity

Answer 6

Work

Question 7

SI unit of Work

Answer 7

Joule

Question 8

T or F. You do not do work by exerting a force on a body while it moves from one place to another.

Answer 8

F. You do work by exerting a force on a body while it moves from one place to another.

Question 9

Formula for Work

Answer 9

W=Fs (force times displacement); W=Fscosθ

Question 10

Can work be zero?

Answer 10

Yes. Work can be (+), (-), or 0.

Question 11

How does work become positive?

Answer 11

If the force has a component in the direction of the displacement

Question 12

How does work become negative?

Answer 12

If the force has a component opposite the direction of the displacement

Question 13

How does work become zero?

Answer 13

If the force is perpendicular to the direction of the displacement

Question 14

Is there work being done on a box sliding freely along a ramp?

Answer 14

None. If it is being pushed, then there is work.

Question 15

Formula for Work-Energy Theorem

Answer 15

W = Kf-Ki = ΔK (Net work done on an object equals the object’s change in kinetic energy.)

Question 16

If work is positive, Kf > Ki, speeding ______.

Answer 16

up

Question 17

If work is negative, Kf > Ki, speeding ______.

Answer 17

down

Question 18

If Ki=0, W = ______.

Answer 18

Kf. KE of an object is equal to the total work that was done to accelerate it from rest to its present speed.

Question 19

How to compute for work and energy with varying forces?

Answer 19

Sum of the areas under the curve approximates the total work done

Question 20

Amount of energy transferred or converted per unit time; scalar quantity

Answer 20

Power

Question 21

SI unit of Power

Answer 21

Watt [W] = [Joules/sec]

Question 22

English system unit of Power

Answer 22

horsepower

Question 23

Conversion factor of horsepower

Answer 23

1 HP = 735.7 Watts

Question 24

Formula for average Power

Answer 24

Pave = ΔW/Δt

Question 25

Formula for Instantaneous Power

Answer 25

P = lim Δt→0 ΔW/Δt = dW/dt