A weight force of 10 N force acts on an object while the object moves 20m along horizontal ground. How much work is done by the weight force on the object? a) 0.5 J b) 2 J c) 10 J d) zero e) 200 J I already know it's not 200 J because I got the question wrong. Please show work!

e) 200 J

Explanation:

Work done by a force on an object is the energy required for a force to move that object over a distance. It can be calculated using the formula:

W = F × d

Where; W = work done

F = force applied

d = distance

According to this question, F = 10N, d = 20m

W = 10 × 20

W = 200 J or N/m

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

magnityde and direction