Answer:
T - M g - Ff = M a describes the acceleration of the object
T = M g + Ff if the object moves at constant speed (a = zero)
Ff = μ M g = .3 * 40 * 9.8 = 118 N the force of friction
Ff will be in a direction opposite to the motion
M g = 40 kg * 9.8 m/s = 392 N
a) T = M g + Ff for an object moving upwards
T = 392 + 118 = 510 N
b) T = M g - Ff for an object moving downwards
T = 392 - 118 = 274 N
Answer:
b. The speed of light is 2.99792458 x 10^8 meters/second.
Explanation:
Speed of light is a universal constant and its value is same throughout the universe . So alien living near Alpha Centauri will quickly understand about it . But other statements are not universal . Mass of electron can vary as per relativistic formula of Einstein . Similarly , mass of proton can also vary according to relativistic concept . It depends upon the velocity of particle . So, the ratio of mass of proton and mass of electron will also vary from one star to another .
Answer:
7.8
Explanation:
Here, an effort of 50 N is applied at the car key and overcomes the resistance(or load) of 390 N at the lid.
mechanical advantage
=load/effort
=390 N/50 N
=7.8
Answer:
0.21%
Explanation:
We are given;
Mass; m = 100 kg
Diameter; d = 2.2 mm = 2.2 × 10^(-3) m
Young's modulus; E = 12.5 x 10^(10) N/m².
Formula for area is;
A = πd²/4
A = (π/4) x (2.2 x 10^(-3))²
A = 3.8 x 10^(-6) m²
Force; F = mg
g is acceleration due to gravity and has a constant value of 9.8 m/s²
F = 100 × 9.8
F = 980 N
Formula for young's modulus is;
E = Stress/strain
Formula for stress = F/A
Formula for strain = ΔL/L
Thus;
E = (F/A)/(ΔL/L)
Making ΔL/L the subject, we have;
ΔL/L = (F/A)/E
Plugging in the relevant values;
ΔL/L = 980/(3.8 x 10^(-6) × 12.5 × 10^(10))
ΔL/L = 0.0021
Then percentage increase in length of a wire = 0.0021 × 100% = 0.21%
