Answer:
change in gravitational potential energy Δ PE = 392 J
Explanation:
given data
mass of the person m = 80 kg
height of the centre of mass Δh = 0.50 m
to find out
change in gravitational potential energy
solution
we get here change in gravitational potential energy that is express here as
change in gravitational potential energy Δ PE = m × g × Δh .........1
put here value we get
change in gravitational potential energy Δ PE = m × g × Δh
change in gravitational potential energy Δ PE = 80 × 9.8 × 0.50
change in gravitational potential energy Δ PE = 392 J
Work = (force) x (distance)
Force = weight of the barbell = (mass) x (gravity) = (2.5 kg) x (9.8 m/s²)
Work = (2.5 x 9.8 newtons) x (3 meters) = 74 newton-meters = 74 joules.
It takes 74 joules to lift the 2.5-kg load 3 meters up off the floor.
After that, as long as the load is held motionless, no more work is done.
Answer:
577g
Explanation:
Given parameters:
Temperature change = 5.9°C
Amount of heat lost = 427J
Unknown:
Mass of the block = ?
Solution:
The heat capacity of a body is the amount of heat required to change the temperature of that body by 1°C.
H = m c Ф
H is the heat capacity
m is the mass of the block
c is the specific heat capacity
Ф is the temperature change
Specific heat capacity of lead is 0.126J/g°C
m = H / m Ф
m = 
= 577g
Mass of the lead block is 577g
Answer:
The centripetal acceleration is 6.95 m/s²
Explanation:
Given;
angular displacement of the blade, θ = 90.08⁰
duration of motion of the blade, t = 0.4 s
radius of the circle moved by the blade, r = 0.45 m
The angular speed of the blade in radian is calculated as;
The centripetal acceleration is calculated as;
a = ω²r
a = (3.93)² x 0.45
a = 6.95 m/s²
Answer:
A force
Explanation:
A push or a pull is an example of a force and can cause an object to speed up, slow down, etc.. Newton's laws tell us that 1- an object will not change its motion unless a force acts on it 2- the force on an object is equal to its mass times its acceleration. 3- The third law states that for every action (force) in nature there is an equal and opposite reaction.. However, forces like gravity and friction can resist movement.
