Answer: Work W = 0
Explanation: Work W = F·s. Because rock does not move, s = 0 and
work done is zero.
Answer:
Upthrust = 20 N
Explanation:
The question says that "A body weighs 100N in air and 80N when submerged in water. Calculate the upthrust acting on the body
?"
Upthrust is defined as the force when a body is submerged in liquid, then liquid applies a force on it.
ATQ,
Weight of body in air is 100 N
Weight of body in water is 80 N
Upthrust is equal to the weight of body in air minus weight of body in water.
Upthrust = 100 N - 80 N
Upthrust = 20 N
So, 20 N of upthrust is acting on the body.
Answer:
The time is 106.7 minute.
Explanation:
Given that,
Density 
Current 
Diameter of wire = 1.2 mm
Length = 31 cm
We need to calculate the drift velocity
Using formula of drift velocity


Put the value into the formula


We need to calculate the time
Using formula for time


Where, l = length
= drift velocity
Put the value into the formula



Hence, The time is 106.7 minute.
Answer:

Explanation:
Given that the operating cost is
cents per mile
total miles covered is given as

so total cost of drive is given as
$
time taken by the truck to move the distance is given as

So total earnings of the driver is given as
$
now total profit of the driver is given as
$
to maximize the profit we have


so we have
