Physics: A1400-kg car moving with a speed of 32 m/s is approaching a stoplight. the light turns yellow and the car makes an abrupt stop over a distance of 60 meters. the amount of work done on the car approximately. a. 84,00 j b. 268, 800 j c. 716, 800 j d. 840,000 j e. 2, 688,000 j f. none of these are correct.

A1400-kg car moving with a speed of 32 m/s is approaching

psychiclion

15.01.2022

c. 716, 800 J

Explanation:

t = Time taken

u = Initial velocity = 32 m/s

v = Final velocity = 0

s = Displacement = 60 m

a = Acceleration

m = Mass of car = 1400 kg

$v^2-u^2=2as\\\Rightarrow a=\dfrac{v^2-u^2}{2s}\\\Rightarrow a=\dfrac{0^2-32^2}{2\times 60}$

Work done is given by

$W=Fscos\theta\\\Rightarrow W=mascos\theta\\\Rightarrow W=1400\times \dfrac{0^2-32^2}{2\times 60}\times 60\times cos0\\\Rightarrow W=-716800\ J$

The amount of work done to stop the car is 716800 J

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miguelelmenor910

19.04.2023

0.2 km/m east

Explanation:

The magnitude of Walt's velocity is given by:

where

s is Walt's displacement

t is the time taken

In this problem, Walt's displacement is s=5 km, while the time taken is t=25 m, so the velocity is

and the direction is east, since Walt is running eastwards.

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