Question

A running back weighing 100 kg runs headlong into a defender weighing 120 kg. The two players are moving at 7 m/s and 5 m/s, respectively. Calculate the total momentum and the total kinetic energy of the system. [Calculations including velocity should reflect direction of travel.]

Answer 1

Step-by-step explanation:

we know that momentum is given as

P=mv

given data

P1=?

mass m1=100kg

velocity v1=7m/s

P2=?

mass m2=120kg

velocity v2=5m/s

the total momentum =P1+P2

total=m1v1+m2v2

total= 100*7+120*5

total=700+600

total= 1300kgm/s

total kinetic energy

KE total= 1/2m1v1^2+1/2m2v2^2

KE total= 1/2*100*(7)^2+1/2*120*(5)^2

KE total= 1/2*100*49+1/2*120*25

KE total= 1/2*4900+1/2*3000

KE total=2450+1500

KEtotal=3950 J