A 2 kg ball has a velocity of 30 m/s.
(a) What is the kinetic energy of the ball?
J
(b) How much work would be required to stop the ball?
J
2007-02-05 17:21:29 · 2 answers · asked by bibun 2 in Science & Mathematics ➔ Physics
(a):
k.e = 1/2 mv^2
= 1/2 x 2 x 30^2
= 900 J
(b):
To stop the ball, same amount of energy but opposite direction of energy have to apply on it, that is 900 J.
2007-02-05 17:30:47 · answer #1 · answered by li mei 3 · 0⤊ 0⤋
Kinetic Energy (KE) equals,
KE = 1/2 mv^2
Where m is the mass of the ball and v is the speed of the vall.
m = 2 kg
v = 30 m/s
KE = 1/2 (2 kg) (30 m/s)^2
KE = 900 Joules
In order to stop the ball work must be done on it in order to change its Kinetic Energy. The amount of work done on the ball will equal the change in its Kinetic Energy. When the ball comes to a stop, KE = 0 (since v = 0).
So the work needed to be done in order to stop the ball will be 900 Joules.
2007-02-06 01:32:07 · answer #2 · answered by mrjeffy321 7 · 0⤊ 0⤋