Question

6.a. A racing car has a uniform acceleration of 4 m/s? What distance will it cover in
10 s after start?
b. A train is travelling at a speed of 90 km/h. Brakes are applied so as to produce
a uniform acceleration of - 0.5m/s?. Find how far the train will go before it is
brought to rest?​

Answer 1

6.a

Given that,

• A racing car starts with a uniform acceleration, a = 4 m/s² .

We have to find the,

• Distance travelled after 10 seconds of starting.

We have,

• Acceleration, a = 4 m/s²
• Time, t = 10 ssecond
• Initial velocity, u = 0 m/s

Using the second equation of motion, Distance travelled can be calculated as,

⇒ s = ut + 1/2 at²

⇒ s = 0×10 + 1/2 × 4 × 10²

⇒ s = 1/2 × 400

⇒ s = 200 m

Hence, The racing car would cover 200 m after 10 seconds of starting.

6.b

Given that,

A train is travelling with a initial velocity, u = 90 km/h applies which results in an acceleration of a = -0.5 m/s².

We have to find the distance travelled by the train before it comes to rest.

First, Make all the units same (Distance in m and time in seconds)

So, After conversion, we have,

• Initial Velocity, u = 25 m/s
• Acceleration, a = -0.5 m/s²
• Final Velocity, v = 0 m/s

Final Velocity is zero because the train comes to rest.

Using the third equation of motion, Distance travelled can be calculated as,

⇒ 2as = v² - u²

⇒ 2 × -0.5 × s = 0 - (25)²

⇒ -s = -625

⇒ s = 625

Hence, The train will cover 625 m before it comes to rest.

Answer 2

Answer:

6.a

Given that,

A racing car starts with a uniform acceleration, a = 4 m/s² .

We have to find the,

Distance travelled after 10 seconds of starting.

We have,

Acceleration, a = 4 m/s²

Time, t = 10 ssecond

Initial velocity, u = 0 m/s

Using the second equation of motion, Distance travelled can be calculated as,

⇒ s = ut + 1/2 at²

⇒ s = 0×10 + 1/2 × 4 × 10²

⇒ s = 1/2 × 400

⇒ s = 200 m

Hence, The racing car would cover 200 m after 10 seconds of starting.

6.b

Given that,

A train is travelling with a initial velocity, u = 90 km/h applies which results in an acceleration of a = -0.5 m/s².

We have to find the distance travelled by the train before it comes to rest.

First, Make all the units same (Distance in m and time in seconds)

So, After conversion, we have,

Initial Velocity, u = 25 m/s

Acceleration, a = -0.5 m/s²

Final Velocity, v = 0 m/s

Final Velocity is zero because the train comes to rest.

Using the third equation of motion, Distance travelled can be calculated as,

⇒ 2as = v² - u²

⇒ 2 × -0.5 × s = 0 - (25)²

⇒ -s = -625

⇒ s = 625

Hence, The train will cover 625 m before it comes to rest.

Explanation:

Hope this answer will help you.