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I need to find wfg,wnet,the acceleration of the car and how long will it take Tyler to get to the gas station

I need to find wfg,wnet,the acceleration of the car and how long will it take Tyler-example-1
User Ponaguynik
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1 Answer

15 votes
15 votes

The free body diagram representing this scenario is shown below

From the information given.

mass of car = 1200kg

Recall,

weight = mg

where

m = mass

g = acceleration due to gravity = 9.8 m/s^2

Thus,

weight of car = 1200 x 9.8 = 11760 N

Normal reaction, N has same magnitude with the weight but the direction is opposite. thus,

N = 11760 N

Frictional force = N x coefficient of friction

From the information given,

coefficient of friction = 0.67

Thus,

Frictional force = 11760 x 0.67 = 7879.2 N

Net force of the car = applied force - frictional force

applied force = 1.3 x 10^4 N = 13000 N

Thus,

Net force = 13000 - 7879.2 = 5120.8N

Recall,

net force = mass x acceleration

acceleration = net force/mass = 5120.8/1200 = 4.27 m/s^2

We want to calculate the time it will take Tyler to get to the gas station. We would apply one of Newton's equation of motion which is expressed as

s = ut + 1/2at^2

where

s = distance covered

t = time

a = acceleration

u = initial velocity

From the information given,

s = 15

a = 4.27

u = 0 because the car was at rest(Since it was broken down)

By substituting these values into the equation, we have

15 = 0 x t + 1/2 x 4.27 x t^2

15 = 0 + 2.135t^2

15 = 2.135t^2

Dividing both sides of the equation by 2.135, we have

15/2.135 = 2.135t^2

t^2 = 7.026

t = square root of 7.026

t = 2.65

The time required is 2.65 s

I need to find wfg,wnet,the acceleration of the car and how long will it take Tyler-example-1
User Hatted Rooster
by
2.7k points