a50g ball is hit to roll by a force of 100N.it rolls over 20m.what was its initial speed
To find the initial speed of the ball, we can use the principle of conservation of mechanical energy.
The ball is initially at rest and is then hit by a force of 100N to start rolling. As it rolls over a distance of 20m, we need to find its initial speed before the force was applied.
Using the equation for kinetic energy and potential energy:
KE (kinetic energy) = PE (potential energy)
Since the ball was initially at rest, its initial kinetic energy is zero. The potential energy can be calculated using the weight of the ball and the distance it rolls. The potential energy formula is given by:
PE = mgh,
where m is the mass of the ball, g is the acceleration due to gravity (9.8 m/s^2), and h is the vertical height.
In this case, there is no vertical height, so the potential energy is zero. Therefore, KE = PE = 0.
The kinetic energy (KE) is given by:
KE = (1/2)mv^2,
where m is the mass of the ball and v is the initial velocity.
Since KE = 0, the equation becomes:
0 = (1/2)mv^2.
Rearranging the equation to solve for v:
v^2 = 0,
v = 0.
Therefore, the initial speed of the ball before the force was applied is 0 m/s.