How is Work Done Calculated for a Car Accelerating Uphill?

AI Thread Summary
To calculate the work done by a car of mass 980 kg accelerating uphill at a 10° incline, one must consider both kinetic and potential energy changes, as well as resistive forces. The work done is determined using the formula: work done = Δkinetic energy + Potential energy + resistive forces. The calculations yield a work done of 161 kJ, but there is a discrepancy noted, leading to a revised total of 175 kJ. It is important to ensure that forces are multiplied by distance to maintain consistent units of Nm. Accurate unit conversion is crucial for correct work done calculations.
MMCS
Messages
151
Reaction score
0
if a car of mass 980kg accelerates up an incline (10°to the horizontal) and increases its speed from 8.3m/s to 13.8m/s in 60m, both the air resistance and rolling resistance are taken as constant at 50N and 200N respectivelyfor the acceleration period described, determine work done

work done = Δkinetic energy + Potential energy

kinetic energy = 1/2 * mass * (v22-v12)
PE = mgh

work done = 1/2 * 980 * (13.82-8.32) + 980 * 9.81 * 60sin(10) + 50N + 200N = 161KJ

but I have the answer to be 175KJ
 
Physics news on Phys.org
Hi MMCS! :smile:
MMCS said:
… + 50N + 200N = 161KJ

Anything strike you as odd about those units? :wink:
 
Ah of course, multiply these forces by the the distance to get units of Nm. Thanks tiny-tim!
 

Thread 'Errors and significant figures'

I multiplied the values first without the error limit. Got 19.38. rounded it off to 2 significant figures since the given data has 2 significant figures. So = 19. For error I used the above formula. It comes out about 1.48. Now my question is. Should I write the answer as 19±1.5 (rounding 1.48 to 2 significant figures) OR should I write it as 19±1. So in short, should the error have same number of significant figures as the mean value or should it have the same number of decimal places as...
View full post »
Thread 'A cylinder connected to a hanging mass'

Thread 'A cylinder connected to a hanging mass'

Let's declare that for the cylinder, mass = M = 10 kg Radius = R = 4 m For the wall and the floor, Friction coeff = ##\mu## = 0.5 For the hanging mass, mass = m = 11 kg First, we divide the force according to their respective plane (x and y thing, correct me if I'm wrong) and according to which, cylinder or the hanging mass, they're working on. Force on the hanging mass $$mg - T = ma$$ Force(Cylinder) on y $$N_f + f_w - Mg = 0$$ Force(Cylinder) on x $$T + f_f - N_w = Ma$$ There's also...
View full post »

Similar threads

Homework: Calculate the work done to accelrate a car
Replies
1
Views
1K
Solving for Work Done When Accelerating a Mass
Replies
3
Views
718
Regarding the work done against air resistance
Replies
2
Views
3K
Work Done by Elevator Cable in Sample Problem 7-6
Replies
2
Views
3K
Calculating Work Done by Car Engine
Replies
8
Views
2K
What is the work done by braking force on a decelerating car?
Replies
11
Views
2K
Calculating work done by a force?
Replies
3
Views
4K
Finding Acceleration of a Car Where Crumpling Occurs (Momentum)
Replies
9
Views
2K
How is the minimum work needed to push a car up an inclined plane calculated?
Replies
4
Views
3K
Work Done by Crane: Calculating Force & Acceleration
Replies
12
Views
9K

Hot Threads

Recent Insights

Back
Top