Yes this is true fluids have mass so they exert force
Explanation:Example
A 500 W television set is switched on for 4 hours. Calculate the energy transferred.
500 W = 500/1000 = 0.5 kW
energy transferred = power × time
= 0.5 × 4
= 2 kWh
Initial conditions:
m1 = 1.0 ; v1 = 5
m2 = 4.0 ; v2 = 0
In the case where the second object (sometimes called the target) is at rest the velocities after the condition are
v1' = v1* (m1-m2)/(m1+m2)
v2' = 2v1*m1/(m1+m2)
For this we get
v1' = 5*(-3)/5 = -3m/s (moving in the opposite direction as before at 3m/s
v2' = 2*5*(1)/5 = 2m/s in the same direction as the original ball was moving
you can see these directions by looking at the signs. The momenta also add to the initial momentum as required.
PART a)
By energy conservation we can say
divide whole equation by mass "m" and plug in all given data
![9.8(1.24) + \frac{1]{2}(1.7)^2 = 9.8(0) + \frac{1}{2}(v)^2](https://tex.z-dn.net/?f=9.8%281.24%29%20%2B%20%5Cfrac%7B1%5D%7B2%7D%281.7%29%5E2%20%20%3D%209.8%280%29%20%2B%20%5Cfrac%7B1%7D%7B2%7D%28v%29%5E2)
so gymnast will reach the floor with speed 5.21 m/s
PART b)
Now the gymnast bend her knees by 0.1 m and comes to rest
so here we will have
now the force on the gymnast will be
so during landing the force will be 6798.5 N
