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Please help me with this static friction problem; It has six parts!

Please help me with this static friction problem; It has six parts!-example-1
User Clemej
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1 Answer

3 votes
Answer:

a) The car's acceleration during the first 20 s = 1 m/s²

b) Net force applied by the engine during the first 20 s = 2000 N

c) The car's acceleration from 20 s to 40 s = 0 m/s²

d) Net force applied by the engine during 20 s to 40 s = 0 N

e) The car's acceleration from 40 s to 50 s = -2 m/s²

f) The net force applied by the engine during the time 40s to 50s = -4000 N

Step-by-step explanation:

The mass of the car, m = 2000 kg

a) Acceleration in the first 20 seconds

In the first 20 seconds, the car's speed increases from 0 m/s to 20 m/s

The final velocity, v = 20 m/s

The initial velocity, u = 0 m/s

Time taken, t = 20 s

Using the equation v = u + at

20 = 0 + 20a

20 = 20a

a = 20/20

a = 1 m/s²

b) Net force applied applied by the engine during the first 20 seconds

F = ma

F = 2000(1)

F = 2000 N

c) Acceleration from 20 s to 40 s

Note that the velocity of the car does not change (is constant) between 20 s and 40 s. This means that the car does not accelerate within this time interval

Acceleration from 20 s to 40 s = 0 m/s²

d) Net force applied by the engine during 20 s to 40 s

a = 0 m/s²

F = ma

F = 2000(0)

F = 0 N

e) The car's acceleration from 40 s to 50 s

Within this time interval, the car decelerates from 20 m/s to 0 m/s

The initial velocity, u = 20 m/s

The final velocity, v = 0 m/s

Time taken, t = 50 s - 40 s

t = 10 s

Using the equation v = u + at

0 = 20 + 10a

10a = -20

a = -20/10

a = -2 m/s²

The car's acceleration from 40 s to 50 s = -2 m/s²

f) The net force applied by the engine during this time (40s to 50s)

a = -2 m/s²

F = ma

F = 2000(-2)

F = -4000N

User Orry
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6.5k points