Answer:
η = 40 %
Explanation:
Given that
Qa ,Heat addition= 1000 J
Qr,Heat rejection= 600 J
Work done ,W= 400 J
We know that ,efficiency of a engine given as

Now by putting the values in the above equation ,then we get

η = 0.4
The efficiency in percentage is given as
η = 0.4 x 100 %
η = 40 %
Therefore the answer will be 40%.
Answer:
The velocity of the ship relative to the earth V = 9.05 
Explanation:
The local ocean current is = 1.52 m/s
Direction
= 40°
Velocity component in X - direction
= 1.52
°
= 1.164 
Velocity component in Y - direction
= 8 + 1.52
°
= 8.97 
The velocity of the ship relative to the earth

Put the values of
and
we get,
⇒ 
⇒ V = 9.05 
This is the velocity of the ship relative to the earth.
Answer:
(a) B = 2.85 ×
Tesla
(b) I = I = 0.285 A
Explanation:
a. The strength of magnetic field, B, in a solenoid is determined by;
r = 
⇒ B = 
Where: r is the radius, m is the mass of the electron, v is its velocity, q is the charge on the electron and B is the magnetic field
B = 
= 
B = 2.85 ×
Tesla
b. Given that; N/L = 25 turns per centimetre, then the current, I, can be determined by;
B = μ I N/L
⇒ I = B ÷ μN/L
where B is the magnetic field, μ is the permeability of free space = 4.0 ×
Tm/A, N/L is the number of turns per length.
I = B ÷ μN/L
= 
I = 0.285 A
Initially, the spring stretches by 3 cm under a force of 15 N. From these data, we can find the value of the spring constant, given by Hook's law:

where F is the force applied, and

is the stretch of the spring with respect to its equilibrium position. Using the data, we find

Now a force of 30 N is applied to the same spring, with constant k=5.0 N/cm. Using again Hook's law, we can find the new stretch of the spring:
Answer:a=v-u/t
=23-8/3
=5m/s hope you got your answer
Explanation: