Answer:
3.1 m/sec
Step-by-step explanation:
The contained in the flying bag of rice is applied to the stationary cart. Lets calculate the kinetic energy of the flying bag of rice. Kinetic energy (KE) is given by KE = (1/2)mv^2, where m is the mass and v is the velocity.
[Note: a kg*m^2/s^2 is 1 Joule]
KE(rice bag) = (1/2)(8.5kg)(5.5m/s)^2
KE(bag) = 129 Joules
When the bag hits the shopping cart, some of the energy tis transferred to the cart. We aill assume no energy in lost in the collision (conservation of energy). The kinetic energy is now contained in a body with a total mass of 25.9 kg (rice bag plus cart).
Use the kinetic energy expression again, using the same KE from the rice bag, but with a new mass.
KE = (1/2)mv^2
129 Joules = (1/2)(26.9 kg)v^2
129 kg*m^2/s^2 = (1/2)(26.9 kg)v^2
v^2 = (129 kg*m^2/s^2)/(12.95 kg)
v^2 = 9.96 m^2/s^2
v = 3.12 m/s (3.1 m/2 with 2 sig figs)
3.12 m/s will be the velocity of the grocery cart and rice bag. [That's 6.7 miles/hr, for the non-metric inclined]