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Vertical motion near the Earth's surface

PostPosted: April 19th, 2011, 6:33 am
by runner
Yeah, hi.

I'm doing Grade 11 Physics and wonder if I could get some help from this forum. I have two questions:

1. A helicopter is rising vertically with a uniform speed of 14.7ms-1 and a wheel drops off (bummer) when it is 49.0m from the ground. Calculate the time taken for the wheel to reach the ground and its velocity at impact.

2. A balloon is 30.0m above the ground and rising vertically with a uniform speed when a coin is dropped from the balloon's basket (wasn't me). If the coin reaches the ground in 4.00s, what is the speed of the balloon?

I'm using the equation S=ut+1/2a t(squared) but it isn't working out....

Thanks for any help you can give.