Question

A sedan car of mass 200kg is moving with a certain velocity . It is brought to rest by the application of brakes, within a distance of 20m when the average resistance being offered to it is 500N.What was the velocity of the motor car?

Answer 1

Given:-

Mass (M) ⇒ 200Kg

V₁ ⇒ u

V₂ ⇒ 0

S ⇒ 20m

Force (F) ⇒ -500N

We know that

F ⇒ m × a

-500N ⇒ 200 × a

a ⇒ $\frac{-500}{200}$

a ⇒ -2.5m/s²

Now,

V² ⇒ u² + 2as

0 ⇒ u² + (2) (-2.5) (20)

0 ⇒ u² - 100

u² ⇒ 100

u ⇒ 10m/s

∴ Velocity of motor car is 10m/s

Answer 2

Answer:

☆●Given:-

Mass=200kg

Distance =20m

Resistance force =500N.

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☆●To prove :-

What is the velocity of given motor car ?

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☆●Proof:-

Resistance force =m×a

500=200×a

500/200=a

a=2.5m/s^-2

We want to find velocity of the given motor car

V^2 =u^2+2as(V=0)

0=u^2+2×-2.5×20

u^2-100=0

u^2=100

u=root of 100

u=+/-10

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Therefore the velocity of given motor car is 10m/s .