A50- kilogram student stands on the surface of the earth. what is the magnitude of the gravitational force of the eart

490 N

Explanation:

The magnitude of the gravitational force acting on an object on the surface of the Earth is given by:

where

m is the mass of the object

g = 9.8 m/s^2 is the acceleration due to gravity

In this problem, we have a student with mass m=50 kg, so the force of gravity in this case is

the velocity you are looking for is made up of two parts: horizontally velocity, vh, and its vertical velocity, vv. the actual velocity of the ball will be these two parts added together, and because velocity is a vector then they will need to be added vectorially.  

neglecting air resistance etc etc.,  

the horizontal velocity component will be constant (because there is no accelerating force in the horizontal direction.  

vh = 8 ms-1  

the vertical velocity component has an accelerating force: 'g'.  

using v = u +at where a = g = 9.81 ms-2.  

the vertical component of velocity, vv = 0 + gt = vv =9.81 x 2  

vv = 19.62 ms-1 . the zero appears because the virtical component of velocity at time t=0 is zero. remember, the ball was thrown horizontally.  

how fast it will be moving (it actual path (being a parabola )) will be the vector sum of these two.  

adding vectorally gives: -  

v = sqr root (8^2 + 19.62^2) = sqr root(64+384.9) = 21.18 or 21.2 ms-1

he kicked it 10 feet straight up into the air? i think this works.