Answer:
Law of conservation of momentum states that. For two or more bodies in an isolated system acting upon each other, their total momentum remains constant unless an external force is applied. Therefore, momentum can neither be created nor destroyed.
Explanation:
Hope it helps
Answer:
2.7 Pizzas.
Explanation:
The power required to walk through 5km in 1 hour is 380W.
A watt is basically Jules per second, then we need to standardized this measurement to second.
5km/hr is equal to,

Walking by 2.5 hours is equal to a distance of,

The total energy required then would be,

Then we know that one pizza slice gives
of energy, the total pizza needed are,

<em>Then you need to buy 3 pizza.</em>
Answer:
work output is always less than work input - the ratio is less than 1.
Explanation:
This principle comes from the fact that a machine or system cannot produce more work than is supplied to it, because this would violate the energy conservation law (work is a type of mechanical energy).
In theoretical machines called "ideal machines" the input work is the same as the output work, but these machines are only theoretical because in real applications there is always some type of energy loss, either in heat produced by a machine or processes for its operation, for this reason the output work is always less than the input work.
Regarding the ratio work output to work input:

because work input WI is always greater than work output WO.