Question

Please answer using grade 11 Conservation of Energy and Momentum please!


Thank-you!


You and a colleague are on a spacewalk, repairing your spacecraft that has stalled in deep space. Your 90.0 kn colleague, initially at rest, asks you to throw her a hammer, which has a mass of 3.0 kg. You throw it to her with a velocity of 4.5 m/s [forward].


a) What is her velocity after catching the hammer?


b) What impulse does the hammer exert on her?


c) What percentage of kinetic energy is lost in the collision?

Answer 1

(a)initial momentum = final momentum

So

$$3\times4.5= (3+90)\ v\\or\\v=0.1452\ m/s$$

(b) impulse = change in momentum of hammer=

$$m(v-4.5)=3(0.1452-4.5)=13. 0644\ kg-m/s$$

(C) initial kinetic energy =

$$\frac{1}{2}m\times4.5^2=0.5\times 3\times 20.25=30.375\ J$$

Final kinetic energy

$$\frac{1}{2}(90+3)(0.1452)=6.7518\ J$$

Percentage loss in energy = $\frac{30.375-6.7518}{30.375}\times100= 77 .77\ percent$