Answer:
Step-by-step explanation:
Kinetic Energy has a formula of
and
Potential Energy has a formula of
PE = mgh. The first 2 problems use the KE formula and the next 2 use the PE formula.
Q1. KE = 16 and v = 4 m/s:
and
so
m = 2 kg
Q2. mass = 1 kg and v = 10 m/s:
so
KE = 50 J
Q3. PE = 40, h = 2, g = 9.8:
40 = m(9.8)(2) and
so
m = 2.0 kg
Q4. mass = 2 kg, g = 9.8 m/s/s, h = 20:
PE = 2(9.8)(20) so
PE = 392 J
**I completely disregarded the rules for sig fig's because your numbers were very inexact**