✔ 最佳答案
2(a) Acceleration = (-52-45)/0.02 m/s^2 = 4850 m/s^2
(b) Applied force = 0.145 x 4850 N = 703 N
(c) Impulse = change of momentum = 0.145 x (-52-45) N.s = 14.07 N.s
(d) Change of momentum = 14.07 kg.m/s
(e) Impulse equals to cahnge of momentum, i.e. an applied impulse leads to a change of momentum of an object.
4(a) 30 degrees = 30.pi/180 radians = pi/6 radians
Time between each frame = 1/25 s
Angular velocity = (pi/6)/(1/25) rad/s = pi x 25/6 rad/s = 13.09 rad/s
(b) Linear velocity = 0.85 x 13.09 m/s = 11.13 m/s
(c) Angular momentum = 2.5 x 13.09 kg.m^2/s = 32.73 kg.m^2/s
(d) A longer golf clube has a larger moment of inertia and hence gives a larger angular momentum. Hence, the momentum transfer to the golf ball is higher and the ball will go faster.
2015-04-06 01:13:19 補充：
2(a) The -ve sign only indicates the direction.
2015-04-06 01:16:42 補充：
4(a) The time lapsed between successive frames is 1/25 s = 0.04 s
The club swings pi/6 radians in 0.04 s
Angular speed = (pi/6)/0.04 rad/s
