Answer:
b.
c.
e.
h.
Explanation:
If we consider the ball,the tension is not balance by weight then the force acting will be non zero.It means that train car in not inertial frame of reference.And the same time the train car must accelerated with respected to the earth.It is not moving straight path.When train is in rest position but the string will be at the constant angle.
So the following option are correct:
b.
c.
e.
h.
“Once in a blue moon” is a common expression that has been used for a long time, and which means 'not very often,' or 'very rarely. ' It often refers to an extra full moon; however, it has been used to describe the way the moon actually looked, when for different reasons it had turned a blueish color.
www.loc.gov › astronomy › item
What
Kinetic energy = (1/2) (mass) (speed)²
Since the 'speed' in the KE formula is squared, if the car's speed
increases by 5 times, its kinetic energy increases by (5²) = 25 times.
The loss of kinetic energy in a skid is just the wo0rk done by friction
between the tires and pavement. So the skid distance is proportional
to the initial kinetic energy, and the car must skid 25 times as far when
it enters the skid at the higher speed.
25 x 30m = 750 meters
<span>The equation that relates Wavelength & frequency of electromagnetic waves is :
Velocity (c) = Wavelength (λ) * frequency (f) ------ (1)
Electromagnetic wave velocity (c) = Speed of Light = 3 * 10^8 m/s
From (1),
Wavelength , λ = c / f
λ= (3*10^8)/(980*10^3)
λ = 306.12 m
Minimum height of the antenna for effective transmission = λ * 0.5 = 306.12*0.5
Answer : 153 m (rounded off)</span>
D. The net gravitational force on the astronaut is not balanced by a normal force
