how much work is needed to stop a 20kg bullet moving with a speed of 150m/s?
what is 1/2 m v^2
254M T
To calculate the work needed to stop a moving object, we can use the formula:
Work = (change in kinetic energy)
The initial kinetic energy is given by the equation:
Initial kinetic energy = 0.5 * mass * (initial velocity)^2
The final kinetic energy, when the object comes to a stop, is:
Final kinetic energy = 0
Therefore, the change in kinetic energy is equal to the initial kinetic energy:
(change in kinetic energy) = (Final kinetic energy) - (Initial kinetic energy)
= 0 - (0.5 * mass * (initial velocity)^2)
Now, let's substitute the given values:
mass = 20 kg
initial velocity = 150 m/s
(change in kinetic energy) = 0 - (0.5 * 20 * (150)^2)
Simplifying this equation will give us the answer:
Work = -0.5 * 20 * (150)^2
Calculating this expression, we find:
Work = -0.5 * 20 * 22500
= -225000 Joules
The negative sign indicates that work is done against the motion of the bullet.