Answer:
a)15 N
b)12.6 N
Explanation:
Given that
Weight of block (wt)= 21 N
μs = 0.80 and μk = 0.60
We know that
Maximum value of static friction given as
Frs = μs m g = μs .wt
by putting the values
Frs= 0.8 x 21 = 16.8 N
Value of kinetic friction
Frk= μk m g = μk .wt
By putting the values
Frk= 0.6 x 21 = 12.6 N
a)
When T = 15 N
Static friction Frs= 16.8 N
Here the value of static friction is more than tension T .It means that block will not move and the value of friction force will be equal to the tension force.
Friction force = 15 N
b)
When T= 35 N
Here value of tension force is more than maximum value of static friction that is why block will move .We know that when body is in motion then kinetic friction will act on the body.so the value of friction force in this case will be 12.6 N
Friction force = 12.6 N
Answer:d
Explanation:
Alpha particles are heaviest among alpha, beta and gamma so they have least amount of Penetration compared to both.
Gamma Particles are lightest among three so they can Penetrate most .
The order of Penetration is given by
Alpha< Beta < Gamma
Answer:
r = 3.787 10¹¹ m
Explanation:
We can solve this exercise using Newton's second law, where force is the force of universal attraction and centripetal acceleration
F = ma
G m M / r² = m a
The centripetal acceleration is given by
a = v² / r
For the case of an orbit the speed circulates (velocity module is constant), let's use the relationship
v = d / t
The distance traveled Esla orbits, in a circle the distance is
d = 2 π r
Time in time to complete the orbit, called period
v = 2π r / T
Let's replace
G m M / r² = m a
G M / r² = (2π r / T)² / r
G M / r² = 4π² r / T²
G M T² = 4π² r3
r = ∛ (G M T² / 4π²)
Let's reduce the magnitudes to the SI system
T = 3.27 and (365 d / 1 y) (24 h / 1 day) (3600s / 1h)
T = 1.03 10⁸ s
Let's calculate
r = ∛[6.67 10⁻¹¹ 3.03 10³⁰ (1.03 10⁸) 2) / 4π²2]
r = ∛ (21.44 10³⁵ / 39.478)
r = ∛(0.0543087 10 36)
r = 0.3787 10¹² m
r = 3.787 10¹¹ m
Answer:
a. endothermic
Explanation:
The reaction shown is an endothermic reaction. In such reaction, they require an input of energy.
- Endothermic changes involves absorption of heat from the surrounding.
- The surrounding becomes colder at the end of the reaction.
- When heat is on the reactant side, it suggests a reaction that requires a considerable input of energy.
Answer:
Centripetal force acting on the body = 9.47 N
Explanation:
Mass of body, m = 2 kg
Radius, r = 3 m
It makes one revolution in 5 seconds.
Period, T = 5 s
Centripetal force, F = mrω²
F = 2 x 3 x 1.256² = 9.47 N
Centripetal force acting on the body = 9.47 N
