## If the work required to speed up a car from 11 km/h to 21 km/h is 6.0×103 J , what would be the work required to increase the car’s speed fr

Question

If the work required to speed up a car from 11 km/h to 21 km/h is 6.0×103 J , what would be the work required to increase the car’s speed from 21 km/h to 33 km/h

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1 year 2021-08-14T15:43:40+00:00 1 Answers 13 views 0

1. Explanation:

We need convert the velocities first to m/s and we get the following:

v2 = 21 km/hr = 5.8 m/s

v1 = 11 km/hr = 3.1 m/s

We need to find the mass of the car also for later use do using the work-energy theorem:

$$delta \: w = \frac{1}{2} m(v \frac{2}{2} – v\frac{2}{1} )$$

6.0×10^3 J = (0.5) m [(5.8)^2 – (3.1)^2]

or

m = 499.4 kg

Now we determine work needed delta W to change its velocity from 21 km/hr to 33 km/hr

v2 = 33 km/hr = 9.2 m/s

v1 = 21 km/hr = 5.8 m/s

delta W = (0.5)(499.4)[(9.2)^2 – (5.8)^2]

= 1.3 x 10^4 J