Physics
(a) A pulley cannot have 100% efficiency. Explain why?
(b) How is the unit 'horsepower' related to the SI unit of power?
(c) Write the two uses of radioactivity.
Machines
2 Likes
Answer
(a) As some effort is wasted in overcoming the friction between the strings and the grooves of the pulley as a result the efficiency of a movable pulley is always less than 100%.
(b) 1 horse power = 746 watt.
(c) Uses of radioactivity :
- Many diseases such as leukemia, cancer, etc., are cured by radiation therapy.
- Radioisotopes are used to trace and study the uptake of nutrients by plants. For example, the use of radioactive phosphorous 32P in fertilizers has revealed how phosphorous is absorbed by plants.
Answered By
1 Like
Related Questions
A pendulum is oscillating on either side of its rest position. The correct statement is
- It has only the kinetic energy at its each position.
- It has maximum kinetic energy at its extreme position.
- It has the maximum potential energy at its mean position.
- The sum of its kinetic energy and potential energy remain constant throughout the motion.
Which is used in cure of cancer?
- Na-24
- Fe-59
- Co-60
- None of these
A uniform meter scale is in equilibrium as shown in the figure given below
Calculate the weight of the meter scale.
The distance between two bodies is decreased by a factor of 3. How is the magnitude of gravitational force between them affected ?