Answer:
-700j , 0j, 700j , 38.6j, 0j
Explanation:
from the question we are given given
distance (d) = 20m
frictional force (Ff) = 35N at 25 degree below the horizontal
(a) work done by friction = Ff x d
Ff is negative because from the question it is against the direction of motion
work done = -35 x 20 = 700 j
(b) work done by gravitational force = gravitational force x distance (cos θ) where θ is the angle between the direction of motion ( which is on the x axis ) and the gravitational force (which is on the y axis)
the angle between the x and y axis ( direction of motion and gravitational force) is 90 degrees
cos 90 = 0, therefore work done by gravitational force is 0 j
(c) work done by the shopper = force applied by the shopper x distance
force applied by the shopper is of equal magnitude to the friction force and this is because the shopping cart is moving at constant speed.
therefore
work done by the shopper = 35 x 20 = 700 j
(d) force exerted by the shopper can be calculated from the formula
work done by the shopper = (force exerted by the shopper) x cos θ x distance
where cos θ is the x component of the applied force
force exerted by the shopper becomes = work done / (distance x cos θ)
= 700 / (20 cos 25 ) = 38.6 N
(e) net work done on the cart = net force x displacement
There is no net force because this cart is moving at constant speed and so the net work done is 0 j
