F4 mechanics problem

2007-04-11 7:57 am

a man is pulling a block of 10kg from rest with 80N up an inclined road of 30 degrees. the length of the road is 10m and friction acting on the block is 10N.

Q: how much time does the man take to pull the block to the top?

更新1:

thanks for answering,,,,=) but i dont understand 80- (100sin30 +10) = 10a? anyway....the answer is 3.18s.

更新2:

is 80- (100sin30+10) the net force F=ma?

更新3:

sry its 3.16*

更新4:

WHAT IS THE POWER OF THE MAN?

回答 (1)

Kelvin的SD高達世界

2007-04-11 8:37 am

✔ 最佳答案

80-(100sin30+10)=10a
a =2m/s^2
S=ut+1/2at^2
10=1/2(2)t^2
t = 3.16s
唔知有冇錯^^希望幫到你啦

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