Answer: Uma pedra é largada de uma certa altura e cai em queda livre. a velocidade da pedra durante a queda pode ser expressa por v(t) = -g*t , em que g = 10 m/s2 é a aceleraçío da gravidade e t o tempo transcorrido.
Explanation: This is actually Portuguese, but let's solve it anyways:
the text says something like:
A stone is dropped from a certain height and falls in free fall. the speed of the stone during the fall can be expressed by _______, where g = 10 m / s2 is the acceleration of gravity and t the elapsed time.
The blank is put there by the context.
If you just drop a rock by some given height, then the only force acting on it will be the force of gravity, and this force causes that the acceleration of the rock towards the ground to be equal to g (which is the number above).
So A(t) = -10m/s^2
(the minus sign is because the rock is falling)
If we want the velocity, we must integrate over time, and then we get:
V(t) = -10m/s^2*t + C
where t is time, and C is a constant of integration and takes the place of the initial velocity of the rock, but because the rock was "dropped", there is not an initial velocity, so C = 0
and the velocity of the rock is V(t) = -10m/s^2*t = g*t
Then the complete sentence is:
Uma pedra é largada de uma certa altura e cai em queda livre. a velocidade da pedra durante a queda pode ser expressa por v(t) = -g*t , em que g = 10 m/s2 é a aceleraçío da gravidade e t o tempo transcorrido.
