Question

A car acquires a velocity of 72 km/h in 10sec starting from rest find
a. acceleration,
b. total distance travelled
c. average velocity​

Answer 1

Answer:

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Answer 2

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➝ Given :-

• initial velocity = 0 ( rest )
• final velocity = 72km/hr

⠀⠀⠀⠀⠀⠀⠀ ⠀⠀⠀= 72 × 5/18 = 20m/s

• time taken = 10 sec

➝ To find :-

a. acceleration

b. total distance

c. average velocity

➝ Solution :-

(a) acceleration :-

Using 1st equation of motion,

$\longrightarrow \sf v = u + at$

where,

• v = final Velocity
• u = Initial Velocity
• a = Acceleration
• t = time

$\longrightarrow \sf 20 = 0 + a \times 10$

$\longrightarrow \sf 20 = 10a$

$\longrightarrow \sf a = \cancel \frac{20}{10}$

$\longrightarrow \bold{ \boxed{ \sf a = 2 {ms}^{ - 2} }}$

Hence, Acceleration is 2m/s²

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(b) Total distance travelled

using 2nd equation of motion

$\longrightarrow \sf S = ut + \frac{1}{2} {at}^{2}$

$\longrightarrow \sf S = 0 \times 10 + \frac{1}{2} \times 2 {(10)}^{2}$

$\longrightarrow \sf S = \frac{1}{2} \times 200$

$\longrightarrow \sf S = \cancel \frac{200}{2}$

$\longrightarrow \boxed{ \sf S = 100m}$

Hence, total distance travelled is 100m

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(C) Average Velocity

we know,

$\longrightarrow \sf V_{avg} = \frac{displacement}{time}$

$\longrightarrow \sf V_{avg} = \cancel \frac{100}{10}$

$\longrightarrow \boxed{ \sf V_{avg} = 10 {ms}^{ - 1} }$

Hence, average Velocity is 10m/s