Answer:
e = 0.46 m
Explanation:
From the laws of friction, frictional force, F is proportional to normal reaction, R.
F₁ = μR
where μ is coefficient of friction; R = mg and g = 9.8 ms⁻²
Also, from Hooke's law, extension, e, in an elastic spring is proportional to applied force.
F₂ = Ke
where K is force constant of the spring
Since the box is just about to move, the coefficient of friction involved is static friction.
The force on the spring equals the frictional force experienced by the box the box; F₁ = F₂
Ke = μR
e = μR/K
where μ = 0.65; R = 18 kg * 9.8 ms⁻²; K = 250 N/m
e = (0.65 * 18 * 9.8)/250
e = 0.46 m
When a ray of light passes from one medium to another it changes its path, this phenomenon of light is called the deviation of light.
Answer:
35.5KJ
Explanation:
Heat transferred (Q) = change in internal energy (∆U) + work done (W)
Q = 30KJ, W = 500Nm = 500J = 500/1000KJ = 0.5KJ
∆U = Q - W = 30 - 0.5 = 25.5KJ
∆U = final energy (U2) - initial energy (U1)
U2 = ∆U + U1 = 25.5 + 10 = 35.5KJ
1. Stopping a car
2. Keeps us from slipping
3. Allows us to grip things and not drop them