D
The student's conclusion shows experimental bias
Just because most of nis classmates like puffed cereal ,it is inappropriate to conclude puffed cereal is better than oats cereal
The thermal efficiency of an engine is

where
W is the work done by the engine
Q is the heat absorbed by the engine to do the work
In this problem, the work done by the engine is W=200 J, while the heat exhausted is Q=600 J, so the efficiency of the machine is
Answer:
(a) 37.5 kg
(b) 4
Explanation:
Force, F = 150 N
kinetic friction coefficient = 0.15
(a) acceleration, a = 2.53 m/s^2
According to the newton's second law
Net force = mass x acceleration
F - friction force = m a
150 - 0.15 x m g = m a
150 = m (2.53 + 0.15 x 9.8)
m = 37.5 kg
(b) As the block moves with the constant speed so the applied force becomes the friction force.

Answer:
Part a)

Part b)

Explanation:
Part a)
Initial value of magnetic flux is given as


so we have

Final flux through the loop is given as

now EMF is given as



Part b)
If magnetic field is constant while Area is changing
So EMF is given as


