Explanation:
Given :
Initial angular velocity =w_i= 215 rev/min
Final angular velocity =w_f= 0
Number of revolutions=n =75.0 rev
Using relation
Converting to rad/s^2
Answer: the true statement form the given statements is “the athletes is not doing any work because he does not move weight”
Answer:
q = 7.542 x 10⁻⁷ C = 754.2 nC
Explanation:
The Coulomb's Law gives the magnitude of the force of attraction or repulsion between two charges:
F = kq₁q₂/r²
where,
F = Force of attraction or repulsion = 0.2 N
k = Coulomb's Constant = 9 x 10⁹ N m²/C²
r = distance between charges = 16 cm = 0.16 m
q₁ = magnitude of 1st charge
q₂ = magnitude of 2nd charge
Since, both charges are said to be equal here.
q₁ = q₂ = q
Therefore,
0.2 N = (9 x 10⁹ N m²/C²)q²/(0.16 m)²
(0.2 N)(0.16 m)²/(9 x 10⁹ N m²/C²) = q²
q = √(5.88 x 10⁻¹³ C²)
<u>q = 7.542 x 10⁻⁷ C = 754.2 nC</u>
Application of surface tension:
1) A needle placed on water can be made to float due to the surface tension of water.
2) Mosquito eggs can float on water because of its surface tension.
3) Toothpaste contains soap, which reduce the surface tension and helps it spread freely in the mouth.
Newton’s first law of inertia
Less force, same work
