# Calculating Work

1. Oct 21, 2016

### Veronica_Oles

1. The problem statement, all variables and given/known data
calculate work when mass of car is 2400kg and displacement is 200m the car travels at velocity of 26.5m/s then speeds up to 30m/s
2. Relevant equations
M- 2400 kg
Vi - 26.5m/s
Vf- 30 m/s
D- 200 m

3. The attempt at a solution
I am struggling with figuring out how to solve this problem would i have to use the formula w = Ek - Ek? But theb i dont end up usinh displacement is there no need to use it here? Does the question have too much information given?

2. Oct 21, 2016

### Orodruin

Staff Emeritus
What do you think and why?

3. Oct 21, 2016

### CWatters

There are two ways to solve the problem and both give the same answer.

4. Oct 21, 2016

### Veronica_Oles

I think that yes u can solve without displacement. Thats the way i make sense of the question Ek final minus Ek initial!

5. Oct 21, 2016

### Buffu

use $W = {1\over 2}m(v_f^2 - v_i^2)$

6. Oct 21, 2016

### CWatters

You can also solve it by using the displacement and the equations of motion to calculate the acceleration. Then apply Newtons law to give the force. Then work = force * distance. Gives same answer as calculating the change in KE.

7. Oct 21, 2016

### haruspex

Have you quoted the whole question, word for word? It reads a bit strangely.
If so then I applaud the question setter. It should happen much more often that questions include redundant information. Figuring out which information is useful is a necessary skill in the real world.