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Impulse and Impulsive Force
Example 1
A car of mass 600kg is moving with velocity of 30m/s. A net force of 200N is applied on the car for 15s. Find the impulse exerted on the car and hence determine the final velocity of the car.
Answer:
Impulse = F × t = (200) × (15) = 300oNs
Impulse = mv - mu
(3000) = 600v - 600(30)
600v = 3000 + 18000
v = 21000/600 = 35 m/s
Example 2
A car of mass 1000kg is traveling with a velocity of 25 m/s. The car hits a street lamp and is stopped in0.05 seconds.
What is the impulsive force acting on the car during the crash?
Answer:
\begin{gathered}
{\text{Impulsive Force,}} \hfill \\
F = \frac{{m(v - u)}}
{t} \hfill \\
F = \frac{{1000(0 - 25)}}
{{0.05}} \hfill \\
F = -500,000N \hfill \\
\end{gathered}
High Jump
(This image is licenced under the GNU Free Document Licence. The original file is from the Wikipedia.org.)
- During a high jump, a high jumper will land on a thick, soft mattress after the jump.
- This is to increase the reaction time and hence reduces the impulsive force acting on the high jumper.
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