学帮网1.A ball is thrown directly upwardswith an initial velocity of 20m/s.Determine the ball’s maximum height and thetime it will take for the ball to fall from its maximum height to the ground.(10 marks)2.A man hauls a 20kg stone thatis currently resti
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1.A ball is thrown directly upwardswith an initial velocity of 20m/s.Determine the ball’s maximum height and thetime it will take for the ball to fall from its maximum height to the ground.(10 marks)
2.A man hauls a 20kg stone thatis currently resting atop a 300 meter cliff up the mountain side to a height of500 meters.He then casts the stone directly downwards until it reaches thevery base of the mountain (0 meters).What is the total work done on the stone?(Hint:work is the change ofenergy!) (10 marks)
1.A ball is thrown directly upwards with an initial velocity of 20m/s.Determine the ball’s maximum height and the time it will take for the ball to fall from its maximum height to the ground.(10 marks)
h=1/2*m*v^2/(mg)=20 m (here,v^2 stands for v²,g=10 m/s^2)
t=h/g=2 s
2.A man hauls a 20kg stone that is currently resting atop a 300 meter cliff up the mountain side to a height of 500 meters.He then casts the stone directly downwards until it reaches the very base of the mountain (0 meters).What is the total work done on the stone?(Hint:work is the change of energy!) (10 marks)
first the man do work ,then the earth do it .so :
W=mgh+mgh=20*10*300+20*10*300=60000*2=1.2*10^5 J
没有图，而且你是为中考猜题用的，不会猜到的，也不用做了。其实倒不难，主要是打在这上面就不容易了
没有图，而且你是为中考猜题用的，不会猜到的，也不用做了。其实倒不难，主要是打在这上面就不容易了
没有图，而且你是为中考猜题用的，不会猜到的，也不用做了。其实倒不难，主要是打在这上面就不容易了
希望对你能有所帮助。