Answer:
the work done by air resistance is 38.5 J
Explanation:
given information:
mass of the ball, m = 0.25 kg
initial speed, = 40 m/s
final speed, = 30 m/s
horizontal distance, x = 120 m
Δh = 20 m
according to conventional energy
W = -
where
is initial energy
is final energy
E = KE + PE
KE is kinetic energy
PE is potential energy
W = -
= mg + - (mg + )
= mg( )+
= m (gΔh + )
= 0.25 ( (9.8) (20) + )
= - 38.5 J
Answer:
510448 Joules
102089.6 J
13.61194 min
Explanation:
The energy in Joules is 510448 Joules.
20% of energy
The energy is 102089.6 J
Power is given by
The number of minutes is 13.61194 min
An average person consumes around 2000-2500 kcal
This is done in 13.61194 min
In one hour
So, it is easy to consume the calories.
Answer:
Explanation:
The star is revolving the black hole like earth revolves around the sun .so time period of rotation T is given by the following relation
T² = , R is distance between black hole and star , M is mass of black hole
Given T = 4.8 hours
4.8² =
Using the same equation for earth sun system
24² = , Ms is mass of the sun and 50R is distance between the sun and the earth .
Dividing the equation
=
= 2x 10⁻⁴
The correct answer is D. Amount of time and area of physical contact between the substances.
Explanation:
Heat transfer refers to the flow of thermal energy or heat between two or more objects. This process involves multiple factors and implies heat from the hottest object goes to the coldest one until there is an equilibrium. To begin, heat transfer depends on the amount of thermal energy in the objects because objects must have a different amount of thermal energy for heat to flow.
Besides this, the amount of energy that flows depends on the time and the contact between the substances of objects. Indeed, objects need to be in contact or close to each other for heat to transfer, and the time needs to be enough for the process to occur. For example, if you place a pot over the fire just for a few seconds it is likely the heat transferred is minimal, which does not occur if you leave the pot more time. At the same time if the pot is in close contact with fire more heat will be transferred.-