If you'r referring to some objects, it means that the mass of the object is less than the water so it floats. If the mass of an object is greater than the mass of the water, it will sink. Compare it to a balloon, helium makes it rise, while normal air makes it sink.
Answer:
Newtons 1st Law.
Explanation:
Because it states as every object will remain at rest or in uniform motion in a straight line unless compelled to change its state by the action of an external force.
Answer:
1.05045 kg/m³
Explanation:
= Density of air = 1.26 kg/m³
= Density of hot air
= Mass of balloon = 539 kg
g = Acceleration due to gravity = 9.81 m/s²
v = Volume of air in balloon = 
The net force on the balloon will be

Also


The density of hot air inside the envelope is 1.05045 kg/m³
a. 13.23 N
b. 13.2
What you need to do is use this equation:
(m1 + m2) x g
<u><em>hope it helps!</em></u>
Answer:
Explanation:
Given
initial velocity u = 15m/s
Height below the water = 25m
a) Using the equation of motion S = (v+u)/2 * t
25 = 0+15/2 * t
25 = 7.5t
t = 25/7.5
t = 3.33s
Hence it will take 3.33secs to reach the water
b) The horizontal distance is expressed as;
S = Uxt
S = 15(3.33)
S = 50m
Hence the horizontal distance from the cliff where the car entered the water is 50m
c) The velocity of the car v.
Using the equation of motion;
v² = u²+2gS
v² = 15²+2(9.8)(25)
v² = 225+490
v = √715
v = 26.74m/s
Hence the car hit the water at the velocity of 26.74m.s