Answer:
m = 0.51[kg]
Explanation:
Potential energy is defined as the product of mass by gravity by height.

where:
Epot = potential energy = 15 [J]
m = mass [kg]
g = gravity acceleration = 9.8 [m/s²]
h = elevation = 3 [m]
Now replacing:
![E_{pot}=m*g*h\\15=m*9.8*3\\m = 0.51[kg]](https://tex.z-dn.net/?f=E_%7Bpot%7D%3Dm%2Ag%2Ah%5C%5C15%3Dm%2A9.8%2A3%5C%5Cm%20%3D%200.51%5Bkg%5D)
Answer:
this is a difficult question but I will try to answer it answer for this is 3220 a + b b u s y d l new
Answer:2.05 m
Explanation:
Given
Mass of sled 
initial speed 
coefficient of kinetic Friction 
According to work-energy theorem work done by all the forces is change in Kinetic energy

,where d= distance moved



Answer:
20.9 x 10⁵ N
Explanation:
The external air pressure downwards and internal air pressure upwards will cancel out. TH net pressure to be faced will be due to water column of 141 m depth.
Pressure of water = hdg = 141 x 1024 x 9.8 = 14.15 x 10⁵ Pa
Area of hatch = 1.72 x 0.859 = 1.4775 sq m.
Total force required = area x pressure = 14.15 x 10⁵ x 1.4775 = 20.9 x 10⁵ N.