Question

A 5.0 kg bike moving 10 m/s comes to a complete stop in 2 seconds. What is the average force of the brakes on the bike?

Answer 1

The average force of the brakes on the bike is 25.0 N

Step-by-step explanation:

The parameters given in the question are,

Mass, m = 5.0kg

Initial velocity, u = 10 m/s

Time, t = 2 sec

Since the bike came to a complete stop, then

Final velocity, v = 0 m/s

To determine the average force of the brakes on the bike; From Newton's second law of motion, Force is given as

F = ma

Where F is the force in N (Newtons)

m is the mass in kg

and a is acceleration in m/s²

Hence, we will first determine the acceleration.

From one of the equations of kinematics for linear motion,

`v = u + at`

Then,
`a = (v - u)/(t\\)`

Putting the given parameters into the above equation, we get

`a = (0 - 10)/(2)`

`a = (-10)/(2)\\ a = - 5`m/s²

The negative sign indicates deceleration since the bike came to a stop,

Hence,
`a = 5` m/s²

From,

F = ma

F = 5.0 × 5

F = 25.0 N

Answer 2

25 N

Step-by-step explanation:

Force : This is defined as the product of mass and acceleration. The unit of force is Newton or kgm/s².

From the question,

F = ma......................... Equation 1

Where F = Force of the brake, m = mass of the break, a = acceleration.

But,

a = v/t.................. Equation 2

where v = velocity, t = time.

Substitute equation 2 into equation equation 1

F = m(v/t)................ Equation 3

Given: m = 5.0 kg, v = 10 m/s, t = 2 seconds

F = 5(10/2)

F = 25 N.

Hence the average force of the brakes on the bike is 25 N