Atennis player receives a shot with the ball (0.060 0 kg) traveling horizontally at 20.0 m/s and returns the shot with the ball traveling horizontally at 40.0 m/s in the opposite direction. (a) what is the impulse delivered to the ball by the tennis racket? (b) some work is done on the system of the ball and some energy appears in the ball as an increase in internal energy during the collision between the ball and the racket. what is the sum w 2 deint for the ball?

a) 3.6 N.s

b) 36 J

Explanation:

Given:

The mass of ball, m = 0.06 kg

The initial velocity v₁ = -20 m/s

final velocity v₂ = 40 m/s  

Now,

The impulse  is given as:

I= change in momentum

or

I = m( v₂ - v₁)

or

I = 0.06 × (40 - (-20))

or

I = 3.6 N.s

(b) work done = change in kinetic energy

W.D = ΔK.E

W.D =

on substituting the values

W.D =  

W.D = 36 J

most voltage drop calculators want the distance between the source and destination. then internally, they double it so both the source and return wires are calculated. but you need to know which distance the calculator uses so you're not half of what you should be or double what you should be.

most circuit breakers will not take a #6 directly, so the electrician will have to splice on a smaller pigtail. you also have to upsize the grounding wire when you upsized the ungrounded (hot) wire (see note in 250.122). this will preclude using most cable assemblies, as a cable with #6 copper will most likely only have a #10 grounding conductor. you need a #6 grounding conductor if the circuit is 20a. a #8 cable is no better, as it will have a #10 grounding conductor too. but most 20a breakers will take a #8 directly.

in your related post, you didn't say what type of load this is. if it is a light or heater, voltage drop won't be a big issue. if this is a motor, the current needs are huge at startup and the voltage drop can pose a problem. if this is a motor, knowing if the motor is under much load during startup will answer the voltage drop effect (a saw is easier to start than a compressor).

vapour or gas assuming atmospheriv pressure