a girl of mass 40 kg is skating at a constant speed of 1 m/s. supposed she doubles her speed, what will be the change in her kinetic energy?
The formula for kinetic energy is
(1/2)M V^2
Surely you can figure out what happens when V doubles.
To find the change in kinetic energy, we need to first calculate the initial and final kinetic energy of the girl. The formula for kinetic energy is:
Kinetic Energy = 0.5 * mass * velocity^2
Let's calculate the initial kinetic energy first:
Initial Kinetic Energy = 0.5 * mass * initial velocity^2
Given that the mass of the girl is 40 kg and her initial velocity is 1 m/s, we can substitute these values into the formula:
Initial Kinetic Energy = 0.5 * 40 kg * (1 m/s)^2
= 0.5 * 40 kg * 1 m^2/s^2
= 0.5 * 40 kg * 1
= 20 kg m^2/s^2
Now, let's calculate the final kinetic energy after she doubles her speed:
Final velocity = 2 * initial velocity = 2 * 1 m/s = 2 m/s
Final Kinetic Energy = 0.5 * mass * final velocity^2
Substituting the values into the formula:
Final Kinetic Energy = 0.5 * 40 kg * (2 m/s)^2
= 0.5 * 40 kg * 4 m^2/s^2
= 0.5 * 160 kg m^2/s^2
= 80 kg m^2/s^2
To find the change in kinetic energy, subtract the initial kinetic energy from the final kinetic energy:
Change in Kinetic Energy = Final Kinetic Energy - Initial Kinetic Energy
= 80 kg m^2/s^2 - 20 kg m^2/s^2
= 60 kg m^2/s^2
Therefore, the change in her kinetic energy will be 60 kg m^2/s^2.