Question

A car of mass 1,000 kg moving with a velocity of 40 km/h^-1 collides with a tree and comes to stop in 5seconds. What will be the force exerted by the car on the tree?

Answer 1

Answer:

2200N

Step-by-step explanation:

convert velocity to m/s = 11m/s

a = (v-u)/t

a = 2.2

f = mass x acceleration

f = 1000 x 2.2

f = 2200N

Answer 2

Solution:

To find force at first we have to find the acceleration.

Calculating Acceleration

Initial velocity = 40kmh⁻¹ = 5/18 × 40 = 11.11 ms⁻¹

Final velocity = 0ms⁻¹

Time = 5s

Acceleration = ??

$\boxed{v = u + at}$

$\therefore \boxed{a = \frac{v - u}{t}}$

$\implies \: a = \frac{0 - 11.11}{5}$

$\implies \: a = \frac{ - 11.11}{5}$

$\implies \: a = - 2.222ms^{ - 2}$

Hence, acceleration/retardation is -2.222ms⁻².

Note : -ve sign denotes retardation here.

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Calculating Force

Mass = 1000kg

Acceleration = -2.222ms⁻²

Force = ??

$\boxed{F = m \times a}$

$\implies \:F = 1000 \times ( - 2.222)$

$\implies \: F = -2222N$

Thus, force exerted by the car on the tree is -2222N

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Additional Information:

Three equations of motion.

1. v = u + at

2. s = ut + 1/2 at²

3. v² = u² + 2as

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