Work and Energy
Energy is defined as :
- The ability to do work
- The amount of work done
If you push an object through a certain distance (d), using a force (F), you can calculate the amount of work done , (W) required in moving the object.
The drawing below illustrates the above mentionned variables:
WORK = Force X Distance. Note that the distance is in the same direction as the applied force.
W = F X d
W = F X d
Where F is the Force doing the "pushing" and d is the distance the object moves.
The distance and the force must be in the same direction.
In this equation, Force is measured in [N], Newtons and distance is measured in [m], meters.
The Work-Energy Equivalence states that the amount of work done is equivalent to the energy used tp achieve this work, and viceversa.
WORK = Energy
Measured in Joules
1 Joule = 1 Newton-meter
1 J = 1Nm
1 Joule = 1 Newton-meter
1 J = 1Nm
Example 1:
A shopper pushes a grocery cart with a force of 100 N continuously for 50 m.
How much energy is she using up, and how much work is she doing on the cart?
Solution:
Given: F = 100 N
d = 50 m
Find: W
W = F x d
= 100 N x 50 m = 5000 J
Therefore, the shopper uses up 5000 N of Energy in pushing the grocery cart.
At the same time, the work she is doing on the cart is also 5000N since Work = Energy.
