Find the force needed to stop in 8m a mass of 30kg moving at 20m/s
The force needed to stop the mass in 8m is 480N.
This can be calculated using the equation F = m * a, where F is the force, m is the mass, and a is the acceleration. In this case, the acceleration is calculated by subtracting the initial velocity (20m/s) from 0, giving an acceleration of -20m/s2. Plugging this into the equation gives F = 30kg * -20m/s2 = -600N.
However, since the mass needs to be stopped in 8m, the acceleration needs to be increased. This can be done by dividing the distance (8m) by the time (0.4s, which is the time it takes to stop the mass at -20m/s2). This gives an acceleration of -50m/s2, which when plugged into the equation gives F = 30kg * -50m/s2 = -1500N.
Therefore, the force needed to stop the mass in 8m is -1500N + 600N = 480N.