Work: Physics - Science 8

1. WORK
Grade 8 Science

2. 3. Explain how work is related to
energy;
4. Compute work done by a constant
force.
1. Define work scientifically;
2. Identify situations in which work
is done and in which no work is
done;
OBJECTIVES

3. WORK
What is it?

4. • It is scientifically defined as the
product of the force exerted on an
object and the distance the object
moved to the direction of the force.
WORK
W=Fd
Where: W=work
F=Force
d=distance/displacement
work =
Amount of force applied
In the direction of motion
Distance over which the
force is applied
x

5. WORK
A girl pushing a chair
Is there any work done?
YES,
there is work done.

6. WORK
Is there any work done?
No,
there is no work done.
A boy pushing a wall

7. WORK
Is there any work done?
No,
there is no work done.
A waiter carrying a tray

8. Work is done on an object when the force applied to it
covers a distance in the direction of the applied force.
Work is done
No Work is done
No Work is done
WORK

9. WORK
Is there work done?

10. Calculating a Work
WORK
Work is done when the force (F) applied to the object causes the object to
have a displacement (d) in the same direction as the force applied.
W=Fd Where: W=work
F=Force
d=distance/displacement

11. WORK
Unit for Work
James Prescott Joule
One (1) Joule is equal to the work
done or energy expended in
applying a force of one Newton
through a distance of one meter.

12. WORK
Suppose a woman is pushing a grocery cart with a 500 Newton
force along the 7 meters aisle, how much work is done in
pushing the cart from one end of the aisle to the other?
Given:
Required:
Formula:
Solution:
F = 500 N
d = 7 m
W = ?
W = Fd
W = 500 N (7m)
W = 500 Nm
W = 3500 J

13. WORK
Suppose a woman is pushing a grocery cart with a 500 Newton force
along the 7 meters aisle, how much work is done in pushing the cart
from one end of the aisle to the other?
Supposing that a woman is having different amount of forces applied in
pushing the grocery cart with distinct distances. How much is the work?
Group 1
Fore = 350 N
Distance = 6 m
Group 2
Force = 700 N
Distance = 9.2 m
Group 3
Force = 156 N
Distance = 2.6 m
Group 4
Force = 875 N
Distance = 14 m
W=Fd