Calculating Work Homework: Mass 2400kg, Displ. 200m, Vi 26.5m/s, Vf 30m/s

[Veronica_Oles]

Homework Statement

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

Homework Equations

M- 2400 kg
Vi - 26.5m/s
Vf- 30 m/s
D- 200 m

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 don't end up usinh displacement is there no need to use it here? Does the question have too much information given?

 

[Orodruin]

Does the question have too much information given?

What do you think and why?

 

[CWatters]

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

 

[Veronica_Oles]

What do you think and why?

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

 

[Buffu]

Homework Statement

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

Homework Equations

M- 2400 kg
Vi - 26.5m/s
Vf- 30 m/s
D- 200 m

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 don't end up usinh displacement is there no need to use it here? Does the question have too much information given?

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

 

[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.

 

[haruspex]

But theb i don't end up usinh displacement is there no need to use it here?

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.