Question

Practice Problems 2
1. The change in velocity of a motor bike is 54 kmh in one minute. Calculate its acceleration in
(a) ms? (b) kmh-1
|(a) 0.25 ms? (b) 3240 kmh4​

Answer 1

Answer:

• 0.25m/s²
• 3240km/h²

Explanation:

Given:-

• Change in velocity , ∆V = 54km/h = 54×5/18 = 15m/s

• Time taken ,t = 1 min = 60 s

To Find:-

• Acceleration ,a

Solution:-

(a)

As we have to calculate the acceleration of the motor bike.

Acceleration of body is defined as the rate of change of velocity at per unit time.

SI unit of Acceleration m/s².

• a = ∆v/t

where,

• a denote acceleration
• ∆P denote change in Velocity
• t denote time taken

Substitute the value we get

→ a = 15/60

→ a = 1/4

→ a = 0.25 m/s²

• Hence, the acceleration of the motor bike is 0.25m/s².

(b)

Now, Calculating the acceleration in km/h².

It is given that Rate of Change Of velocity 54km/h

And time taken = 1 min = 1/60 hour

→ a = ∆V/t

→ a = 54/1/60

→ a = 54×60/1

→ a = 3240 km/h²

• Hence, acceleration in km/h² is 3240km/h².

Answer 2

Acceleration of motor bike is 0.25 m/s² or 3240km/hr²

Explanatìon :

Given :

• Initial velocity of a car ,u = 0km/hr
• Final velocity of car , v = 54km/hr = 15m/s
• Time interval , t = 1 min = 60 sec

To Find :

Acceleration of the motor bike in

• m/s²
• km/hr²

${\purple{\boxed{\large{\bold{Formula's}}}}}$

Kinematic equations for uniformly accelerated motion .

$\bf\:v=u+at$

$\bf\:S=ut+\frac{1}{2}at{}^{2}$

$\bf\:v{}^{2}=u{}^{2}+2aS$

and $\bf\:s_{nth}=u+\frac{a}{2}(2n-1)$

${\underline{\sf{Answer}}}$

We have ,

• u = 0 m/s
• v= 15 m/s
• t = 60 sec

By using first Equation of motion

$\rm\:v=u+at$

Put the given values , then

$\sf\implies\:15=0+a(60)$

$\sf\implies\:60a=15$

$\sf\implies\:a=\dfrac{15}{60}$

$\sf\implies\:a=\dfrac{1}{4}$

$\sf\implies\:a=0.25ms^{-2}$

We know that

$\sf\:1kmh^{-2}=\dfrac{1}{12960}ms^{-2}$

Then ,

$\sf\implies\:a=3240kmh^{-2}$

Therefore , Acceleration of the motor bike is 0.25m/s² or 3240km/hr²

____________

More information about topic

1. Velocity is a vector quantity.
2. The velocity of an object can be positive, zero and negative.
3. SI unit of Velocity is m/s
4. Dimension of Velocity: $\sf\:[M^0LT{}^{-1}]$