A teacher uses the model that little invisible gremlins speed up or slow down objects and the direction they push gives the dire
2 answers:
You might be interested in
Answer:
0.56
Explanation:
Let the coefficient of friction is μ.
m = 4.3 kg, θ = 30 degree, initial velocity, u = 0, s = 2.7 m, t = 5.8 s
By the free body diagram,
Normal reaction, N = mg Cosθ = 4.3 x 9.8 x Cos 30 = 36.49 N
Friction force, f = μ N = 36.49 μ
Net force acting on the block,
Fnet = mg Sinθ - f = 4.3 x 9.8 x Sin 30 - 36.49 μ
Fnet = 21.07 - 36.49μ
Net acceleartion, a = Fnet / m
a = (21.07 - 36.49μ) / 4.3
use second equation of motion
s = ut + 1/2 a t^2
2.7 = 0 + 1/2 x (21.07 - 36.49μ) x 5.8 x 5.8 / 4.3
By solving we get
μ = 0.56
Answer: gravitational potential energy is converted into kinetic energy
Explanation:
When the diver stands on the platform, at 20 m above the surface of the water, he has some gravitational potential energy, which is given by
where m is the man's mass, g is the gravitational acceleration and h is the height above the water. As he jumps, the gravitational potential energy starts decreasing, because its height h above the water decreases, and he acquires kinetic energy, which is given by
where v is the speed of the diver, which is increasing. When he touches the water, all the initial gravitational potential energy has been converted into kinetic energy.
Answer:
Explanation:
Given
mass of book(m)=2.1 kg
height up to which book is lifted is (h)2.2 m
height of person
Potential energy of book relative to ground=mgh
(b)PE w.r.t to person head =mg(h-h0)
work done by person in lifting box 2.2 m w.r.t floor
Word done =Potential Energy of box relative to floor=45.2 J