Advertisements
Advertisements
Question
A spinning wheel is brought in contact with an identical wheel spinning at identical speed. The wheels slow down under the action of friction. Which of the following energies of the first wheel decreases?
(a) Kinetic
(b) Total
(c) Mechanical
(d) Internal
Advertisements
Solution
(a) Kinetic
(c) Mechanical
The kinetic energy of a body depends on its speed. Since when a spinning wheel is slowed down, its speed decreases leading to reduction in its kinetic energy. The mechanical energy of a body is defined as the sum of its potential and kinetic energies. Since the kinetic energy of the wheel has been decreased, it'll lead to decrease in its mechanical energy. When the wheel slows down due to friction, its mechanical energy gets converted into heat energy, leading to increase in internal energy, which increases with increase in temperature.
APPEARS IN
RELATED QUESTIONS
The dimensions of emissive power are ______.
1000 tiny mercury droplets coalesce to form a bigger drop. In this process, temperature of the drop _______ .
(A) increases
(B) may increase or decrease
(C) decreases
(D) does not change
A spherical shell is heated. The volume changes according to the equation Vθ = V0 (1 + γθ). Does the volume refer to the volume enclosed by the shell or the volume of the material making up the shell?
Which of the curves in the following figure represents the relation between Celsius and Fahrenheit temperatures?
An aluminium sphere is dipped into water at 10°C. If the temperature is increased, the force of buoyancy
In a calorimeter, the heat given by the hot object is assumed to be equal to the heat taken by the cold object. Does it mean that heat of the two objects taken together remains constant?
As the temperature is increased, the time period of a pendulum
A person's skin is more severely burnt when put in contact with 1 g of steam at 100°C than when put in contact with 1 g of water at 100°C. Explain
The heat capacity of a body depends on
(a) the heat given
(b) the temperature raised
(c) the mass of the body
(d) the material of the body
Heat and work are equivalent. This means, ____________ .
A concrete slab has a length of 10 m on a winter night when the temperature is 0°C. Find the length of the slab on a summer day when the temperature is 35°C. The coefficient of linear expansion of concrete is 1.0 × 10–5 °C–1.
A steel wire of cross-sectional area 0.5 mm2 is held between two fixed supports. If the wire is just taut at 20°C, determine the tension when the temperature falls to 0°C. Coefficient of linear expansion of steel is 1.2 × 10–5 °C–1 and its Young's modulus is 2.0 × 10–11 Nm–2.
In hot summer after a bath, the body’s __________.
‘An object contains more heat’- is it a right statement? If not why?
Two tumblers of A and B have water at 50°C temperature. If the water from A and B is poured into tumbler C. The temperature of C is ______.
Heat is measured in Celsius or centigrade.
What is the approximate interatomic spacing in gases at NTP (Normal Temperature and Pressure)?
Which of the following correctly differentiates heat from temperature?
