If my older brother lifts a rock 6 ft in the air and in rock weighs 100 lbs, if It took him 2 seconds to lift the rock how much power was needed? (P=E/t

Answer 1

To calculate the power needed, we need to determine the amount of energy used to lift the rock and the time taken to do so.

First, we calculate the potential energy (E) of the rock lifted using the formula E = mgh, where m is the mass of the rock, g is the acceleration due to gravity (9.8 m/s²), and h is the height.

Given:
Mass of the rock (m) = 100 lbs
Height (h) = 6 ft
Acceleration due to gravity (g) = 9.8 m/s² (convert feet to meters)

Converting the mass of the rock from pounds to kilograms:
Mass (m) = 100 lbs = 100/2.2046 kg

Converting the height from feet to meters:
Height (h) = 6 ft = 6 * 0.3048 m

Now we can calculate the potential energy (E):
E = mgh

Calculating E:
E = (100/2.2046) * 9.8 * (6 * 0.3048)

Next, we find the time taken to lift the rock (t):
Time (t) = 2 seconds

Finally, we can calculate the power (P) using the formula P = E/t:
P = E/2

Calculating P by substituting the values of E and t:
P = (100/2.2046) * 9.8 * (6 * 0.3048) / 2

Now you can calculate P using a calculator to get the final result.