The correct answer to the question is: A) miles/hour and B) metre/ second.
EXPLANATION:
Before answering this question, first we have to understand speed.
The speed of a body is defined as the rate of distance travelled or the distance travelled by a body per unit time.
Hence, it is a derived quantity which is obtained from distance and time.
The unit of distance can be metre, miles, and the unit of time can be second, minutes or hour.
As speed is the distance covered per unit time, the perfect units will be miles/hour and metre/second.
Hence, the correct options are first and second.
Answer:

Given:
Initial velocity (u) = 30 m/s
Final speed (v) = 0 m/s
Acceleration (a) = - 1.5 m/,s²
To Find:
Time in which train will come to rest (t).
Explanation:

So,
Time in which train will come to rest = 20 seconds
Answer:
dV/dt = 9 cubic inches per second
Explanation:
Let the height of the cylinder is h
Diameter of cylinder = height of the cylinder = h
Radius of cylinder, r = h/2
dh/dt = 3 inches /s
Volume of cylinder is given by

put r = h/2 so,

Differentiate both sides with respect to t.

Substitute the values, h = 2 inches, dh/dt = 3 inches / s

dV/dt = 9 cubic inches per second
Thus, the volume of cylinder increases by the rate of 9 cubic inches per second.
Answer:
A blackbody, or Planckian radiator, is a cavity within a heated material from which heat cannot escape. No matter what the material, the walls of the cavity exhibit a characteristic spectral emission, which is a function of its temperature.
Example:
Emission from a blackbody is temperature dependent and at high temperature, a blackbody will emit a spectrum of photon energies that span the visible range, and therefore it will appear white. The Sun is an example of a high-temperature blackbody.
Answer:
An active pendulum has the most kinetic energy at the lowest point of its swing when the weight is moving fastest.
Explanation:
SO YOU HAVE THE LEAST KINETIC ENERGY AT THE HIGHEST POINT OF THE SWING WHEN IT'S NOT ACTIVE