Question

help me to solve this please​

Answer 1

Answer:

Hello Friend

The answer is 2.5m/s^2

Explanation:

Acceleration = Change in Velocity/Time

                      = 100-80/8

                      = 20/8

                      = 2.5m/s^2

Handwritten:

Answer 2

Question: A car decreases its speed from 100 km/h to 80 km/h in 8 seconds. Find the acceleration of the car

Provided that:

• Initial velocity = 100 km/h
• Final velocity = 80 km/h
• Time taken = 8 seconds

To calculate:

• The acceleration

Solution:

• The acceleration = -0.69 m/s²

Using concepts:

• Formula to convert kmph-mps
• Formula to find acceleration

Using formula:

• ${\small{\underline{\boxed{\sf{a \: = \dfrac{v-u}{t}}}}}}$

Where, a denotes acceleration, v denotes final velocity, u denotes initial velocity and t denotes time taken

Required solution:

~ Firstly let us convert kmph-mps!

Converting 100 kmph-mps

$:\implies \sf 100 \times \dfrac{5}{18} \\ \\ :\implies \sf \dfrac{500}{18} \\ \\ :\implies \sf \cancel{\dfrac{500}{18}} \: (Cancelling) \\ \\ :\implies \sf 27.77 \: mps \\ \\ {\pmb{\sf{Henceforth, \: converted!}}}$

Converting 80 kmph-mps

$:\implies \sf 80 \times \dfrac{5}{18} \\ \\ :\implies \sf \dfrac{400}{18} \\ \\ :\implies \sf \cancel{\dfrac{400}{18}} \: (Cancelling) \\ \\ :\implies \sf 22.22 \: mps \\ \\ {\pmb{\sf{Henceforth, \: converted!}}}$

Therefore,

• Initial velocity = 27.77 m/s
• Final velocity = 22.22 m/s

~ Now let us calculate acceleration!

$:\implies \sf Acceleration \: = \dfrac{Change \: in \: velocity}{Time} \\ \\:\implies \sf a \: = \dfrac{v-u}{t} \\ \\ :\implies \sf a \: = \dfrac{22.22 - 27.77}{8} \\ \\ :\implies \sf a \: = \dfrac{-5.55}{8} \\ \\ :\implies \sf a \: = \cancel{\dfrac{-5.55}{8}} \: (Cancelling) \\ \\ :\implies \sf a \: = -0.69 \: ms^{-2} \\ \\ :\implies \sf Acceleration \: = -0.69 \: ms^{-2} \\ \\ :\implies \sf Retardation \: = -0.69 \: ms^{-2}$

Therefore, acceleration is -0.69 m/s sq. And acceleration became retardation (inverse of acceleration) and came in negative because the car slow down its velocity!