Answer:
Simple machines are useful because they reduce effort or extend the ability of people to perform tasks beyond their normal capabilities. Simple machines that are widely used include the wheel and axle, pulley, inclined plane, screw, wedge and lever.
Answer:
10,000 years
Explanation:
Given that,
Half life of the radioactive isotope,
= 5000 years
Initial composition,
= 16 grams
Final composition,
= 4 grams
We know that,

Therefore, the age of the rock is 10,000 years.
Answer:
41.5 m/s
Explanation:
Since there are no external forces, momentum must be conserved.
Momentum P = mv.
Total momentum before the collision:

Total momentum after the collision:

solving for v:
