When you use a slingshot to fire a 500 g rock you stretch the rubber band storing potential energy. The initial elastic potential energy of the rubber band is 85 J and the rock leaves the slingshot with a speed of 18 m/s. Find how much energy is lost to heat.
stored energy - K.E. of rock
85 J - [.5 * 0.5 kg * (18 m/s)^2]
To find the amount of energy lost to heat, we can start by calculating the final kinetic energy of the rock, and then subtracting it from the initial potential energy of the rubber band.
Step 1: Find the final kinetic energy of the rock.
The kinetic energy of an object is given by the formula:
KE = (1/2) * mass * speed^2
Given:
mass of the rock (m) = 500 g = 0.5 kg
speed of the rock (v) = 18 m/s
Using the formula, we can calculate the kinetic energy of the rock:
KE = (1/2) * 0.5 kg * (18 m/s)^2
Step 2: Calculate the energy lost to heat.
The energy lost to heat is the difference between the initial potential energy (85 J) of the rubber band and the final kinetic energy of the rock.
Energy lost to heat = Initial potential energy - Final kinetic energy
Energy lost to heat = 85 J - KE
Substitute the value of KE from step 1 in the equation to get the final answer.