Answer:
Explanation:
When the skier reaches the bottom of the slope , height lost by it
h = 50 sin32 m
= 26.5 m
potential energy lost
= mgh
Gain of kinetic energy
= 1/2 mv²
mgh = 1/2 mv²
v = √ 2gh
= √ (2x9.8 x 26.5)
= 22.8 m /s
b )
Let μ be the coefficient of kinetic friction required.
friction force acting
= μmg
work done by friction in displacement of d (40 m ) on horizontal surface
- μmg x d
This negative work will be equal to positive kinetic energy of the skier on horizontal surface .
= μmg x d = (1/2) m v²
μ = v² / (2 gd)
= 519.4 / (2 x 9.8 x 140 )
= .19
Well, when you want to accomplish a goal, you can't take forever to do it now can you? No. The purpose of setting a deadline for your goal is for motivation. You become motivated to do it, instead of putting it off for later. You want to get it done in a reasonable amount of time.
Given :
The mass of the balloon was 1890 kg and had a volume of 11,430 m3 .
The balloon floats at a constant height of 6.25m above the ground.
To Find :
The density of the hot air in the balloon.
Solution :
We know,
Volume × ( Density of surrounding air - Density of hot air ) = mass
Putting given values in above equation, we get :
Therefore, the density of hot air in the balloon is 1.125 kg m³.
