Answer: 
Explanation:
The acceleration of the motorcycle is given by

where
v=24 m/s is the final velocity of the motorcycle
u=15 m/s is the initial velocity
t=3 s is the time taken
Substituting these numbers into the equation, we find

Answer:
Explanation:
There will not be any internal reflection . it will be only refraction
critical angle = θ
Sinθ = 1 / μg
μg = 1.43 / 1.33 =
Sinθ = 1.33 / 1.43
= .93
θ = 68.44
angle of incidence i = 68.44 / 2
= 34.22
Sin i / Sin r = μw = 1.33 / 1.43
= .93
sin 34.22 / sinθ₁ = .93 , θ₁ is angle of refraction.
sinθ₁ = sin 34.22 / .93
= .5623 / .93
= .6047
θ₁ = 37 degree Ans
Answer:
183333 Pa
Explanation:
The weight of the football player is : 550 N ,thus the force the player exerts on the floor is 550 N
The area of blades in contact with the floor is = 30cm² = 0.003 m²
Pressure = Force / Area
Pressure = 550 / 0.003
Pressure = 183333 Pa
Answer:
Explanation:
Magnitude of force per unit length of wire on each of wires
= μ₀ x 2 i₁ x i₂ / 4π r where i₁ and i₂ are current in the two wires , r is distance between the two and μ₀ is permeability .
Putting the values ,
force per unit length = 10⁻⁷ x 2 x i x 2i / ( 6 x 10⁻³ )
= .67 i² x 10⁻⁴
force on 3 m length
= 3 x .67 x 10⁻⁴ i²
Given ,
8 x 10⁻⁶ = 3 x .67 x 10⁻⁴ i²
i² = 3.98 x 10⁻²
i = 1.995 x 10⁻¹
= .1995
= 0.2 A approx .
2 i = .4 A Ans .
Back emf is 85.9 V.
<u>Explanation:</u>
Given-
Resistance, R = 3.75Ω
Current, I = 9.1 A
Supply Voltage, V = 120 V
Back emf = ?
Assumption - There is no effects of inductance.
A motor will have a back emf that opposes the supply voltage, as the motor speeds up the back emf increases and has the effect that the difference between the supply voltage and the back emf is what causes the current to flow through the armature resistance.
So if 9.1 A flows through the resistance of 3.75Ω then by Ohms law,
The voltage across the resistance would be
v = I x R
= 9.1 x 3.75
= 34.125 volts
We know,
supply voltage = back emf + voltage across the resistance
By plugging in the values,
120 V = back emf + 34.125 V
Back emf = 120 - 34.125
= 85.9 Volts
Therefore, back emf is 85.9 V.