Question

Calculate the momentum of a 2000-kg elephant charging a hunter at a speed of 7.50 m/s . (b) compare the elephant's momentum with the momentum of a 0.0400-kg tranquilizer dart fired at a speed of 600 m/s . (c) what is the momentum of the 90.0-kg hunter running at 7.40 m/s after missing the elephant?

Answer 1

(a) The momentum of a moving object is given by:

$p=mv$

where m is the mass of the object and v is its speed. In this problem, the mass of the elephant is $m=2000 kg$ and its speed is $v=7.50 m/s$, therefore its momentum is

$p=(2000 kg)(7.50 m/s)=15000 kg m/s$

(b) We can use the same formula to calculate the momentum of the tranquilizer dart, whose mass is $m=0.04 kg$ and whose speed is $v=600 m/s$:

$p=mv=(0.04 kg)(600 m/s)=24 kg m/s$

we see that the elephant's momentum is much larger than the momentum of the dart.

(c) Again, using the same formula, the mass of the hunter is $m=90 kg$, his speed is $v=7.40 m/s$, therefore his momentum is

$p=mv=(90 kg)(7.40 m/s)=666 kg m/s$