Question

A car of mass 1.2kg traveling at 45m/s is brought to rest in 9 second . calculate average force applied by the Breck.

Answer 1

Given :

• Mass = 1.2 kg
• Initial velocity = 45 m/s
• Final velocity = 0 m/s
• Time = 9s

To Find :

• Average force applied by break

Solution :

F = ma

F = m * (v - u)/t

F = 1.2 * (0 - 45)/9

F = 1.2 * -45/9

F = 1.2 * -5

F = -6 N

Answer 2

Given :

• Mass (m) = 1.2 kg
• Final velocity (v) = 0 m/s (as it is brought to rest)
• Initial velocity (u) = 45 m/s
• Time (t) = 9 seconds

To find :

• Force

According to the question,

$\bullet \: {\boxed{ \bf \green{v = u + at}}}$

Now according to the formula we will put the value,

$\bf \implies{0 = 45 + a \times 9} \\ \\ \bf \implies{ - 45 = 9a} \\ \\ \bf \implies{ - 5 = a} \: \red\bigstar$

Now we will find force,

$\bullet \: {\boxed { \bf \green{ F= ma}}}$

$\bf \implies {F = 1.2 \times - 5} \\ \\ \bf \implies{ \dfrac{12}{10} \times - 5} \\ \\ \bf \implies {F = - 6 \: N} \green \bigstar$

So,the force is -6 N..