A black of mass 5kg is lifted 2m in 3 seconds find the work done
if on earth and g = 9.81 m/s^2
then
potential energy gained = m g h = 5 * 9.81 * 2 = 98.1 Joules
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HOWEVER it could be more complicated if the thing went up with constant acceleration. In that case it also gained kinetic energy and we need the speed at the top.
v = 0 + a t
h = 0 + 0 + (1/2) a t^2
2 = (1/2) a * 9
a = 4/9
so
v = (4/9) (3) = 4/3 meters/second at height = 2
Ke = (1/2) m v^2 = (1/2) * 5 * 16/9 = 40/9 = 4.44 Joules
in that case 98.1 + 4.4 = 102.5 Joules
I have no idea if the question writer meant for you to do that kinetic energy part
work = force * distance = mgh
To find the work done, we can use the formula:
Work = Force × Distance
First, we need to find the force required to lift the block. The force required can be calculated using Newton's second law of motion:
Force = Mass × Acceleration
Since the block is lifted vertically, the only force acting on the block is the force due to gravity, which can be calculated using the formula:
Force = Mass × Gravity
where Gravity = 9.8 m/s^2 (approximate value on Earth).
Given that the mass of the block is 5 kg, we can calculate the force as follows:
Force = 5 kg × 9.8 m/s^2
= 49 N
Next, we can calculate the work done using the formula:
Work = Force × Distance
Given that the block is lifted a distance of 2 m, we can find the work done as follows:
Work = 49 N × 2 m
= 98 J
Therefore, the work done in lifting the block for a distance of 2 m is 98 Joules.
To find the work done, we can use the equation:
Work = Force x Distance
In this case, the force applied to lift the black mass is equal to its weight, given by:
Force = mass x gravity
where mass = 5kg and gravity = 9.8 m/s² (acceleration due to gravity).
So,
Force = 5kg x 9.8 m/s² = 49 N
The distance lifted is given as 2m.
Now, we can calculate the work done:
Work = Force x Distance = 49 N x 2m = 98 Joules.
Therefore, the work done to lift the black mass is 98 Joules.