Upthrust formula is F=mg-pVg,right?But the question do not give p and V.How can i calculate the upthrust?

Question

kropot72 · Answer

V means volume. Can you please post the full question.

anonymous · Answer

A toy helicopter of mass 5.0kg rises with uniform acceleration from rest until a height of 60 m in 10s. What is the upthrust produced by the helicopter rotor?

kropot72 · Answer

I think that you are looking at a formula related to the upthrust on a body immersed in a liquid, such as water. In that case the formula is of no use in solving the question.

anonymous · Answer

So I want use what formula to solve the question?

kropot72 · Answer

First we need to find the acceleration of the toy using the formula:
$$x=\frac{1}{2}at ^{2}$$
where x is the vertical displacement, a is the acceleration in ms^-2, and t is the time:
$$60=\frac{1}{2}a\ 10^{2}\ ............(1)$$
Can you solve equation (1) to find the acceleration a?
Then we must find the total acceleration produced by the rotor, which will be a plus the acceleration of gravity, g.
$$Total\ acceleration=a _{t}=a+g$$
When we find the acceleration, the next step is to use the following equation:
$$F=ma _{t}$$

anonymous · Answer

OK...Thanks for your help...^_^

kropot72 · Answer

You're welcome :)