Question

the speed time graph of a car is given alongside. The car weighs 1000kg. What is the breaking force applied at the end of 5s to bring the car to a stop within one second​

Answer 1

Answer:

Given quantities:

Mass (m) = 1000 kg

Time (t) = 1 s

Initial velocity [before stopping the car] (u) = 15 m/s

Final velocity (v) = 0 m/s

Acceleration (a) = $\dfrac{v-u}{t}$

Substituting the values,

$\dfrac{0-15}{1}$

= $-15\:m/s^2$

According to Newton's second law of motion,

F = ma

Substituting the values,

F = 1000 x -15

= -15,000 N

Therefore the force applied by the brakes is 15,000 N.

(This can also be written as -15 KN)

Note:

N = Newton

KN = Kilo Newton

Formulas used:

→ derivation of acceleration

→ Newton's second law of motion

Knowledge Bytes:

→ Newton's second law of motion:

Newton's second law of motion states that the rate of change of momentum is directly proportional to the unbalanced force applied in the direction of the force. It is expressed mathematically by the formula F = ma.

→ The SI unit of force is Newton (N).