A) Calling F the intensity of the horizontal force and d the displacement of the block across the floor, the work done by the horizontal force is equal to
b) The work done by the frictional force against the motion of the block is equal to:
Part of these 105.1 Joules of work becomes increase of thermal energy of the block (
), and part of it becomes increase of thermal energy of the floor (
). We already know the increase in thermal energy of the block (38.2 J), so we can find the increase in thermal energy of the floor:
c) The net work done on the block is the work done by the horizontal force F minus the work done by the frictional force (the frictional force acts against the motion, so we must take it with a negative sign):
For the work-energy theorem, the work done on the block is equal to its increase of kinetic energy:
So, we have
Answer:
a) 74.8 V/m
b) direction -(i)
Explanation:
For this case, the electric field is defined as:
because V is a function dependent of x so we can derivate it:
so:
Because of the sign, the magnitude of electric field 74.8 V/m on the negative direction of i vector, thus means towards the plate 1.
Answer:
C.) Gravity
Explanation:
The projectile is an object upon which the only force is gravity. Gravity acts to influence the vertical motion of the projectile.
Her speed is 4.76 miles per hour.
We don't have enough information to find her velocity.