Copy the diagram of the forearm alongside, indicate the positions of the Load, Effort and Fulcrum.
The positions of load, effort and fulcrum is as shown below:
Define ‘joule’, the SI unit of work and establish a relationship between the SI and CGS unit of work?
Joule: One Joule is the work done when a force of 1 N acts on a body and it displaces by 1 m in its own direction.
The SI unit of work is joule.
C.G.S unit of work = ergs
1 J = 1 N × 1 m
What energy conversion take place in the following when they are working:
i) Electricity toaster
i) Electric Energy to heat energy.
ii) Sound energy to electrical energy.
Two isosceles right angled triangle prisms are placed near each other as shown in the figure.
Complete the path of light ray entering the first isosceles right-angled glass prism till it emerges from the second identical prism.
The path of the ray of light entering the first isosceles triangle is as shown below:
In what way will the temperature of water at the bottom of a waterfall be different from the temperature at the top? Give a reason for your answer.
Temperature at the bottom is more, because the potential energy at top converts to heat energy when water reaches at bottom, as a result temperature of water at the bottom increases.
Draw a ray diagram to illustrate the determination of the focal length of a convex lens using an auxiliary plane mirror.
The ray diagram to illustrate the determination of the focal length of a convex lens using an auxiliary plane mirror is as shown below:
When an arrow is shot from a bow, it has kinetic energy in it. Explain briefly from where does it get its kinetic Energy?
When bow is stretched, work is done on it which has elastic potential energy and on releasing it, potential energy is converted into kinetic energy.
i) A monochromatic beam of light of wavelength λ passes from air into a glass block. Write an expression to show the relation between the speed of light in air and the speed of light in glass.ii) As the ray of light passes from air to glass, state how the wavelength of light changes. Does it increase, decrease or remain constant?
Refractive index (μ) increases with decrease in wavelength (λ)
This is because the wavelength of light decreases.
i) A stone of mass 64.0 g is thrown vertically upward from the ground with an initial speed of 20.0 m/s. The gravitational potential energy at a group level is considered to be zero. Apply the principle of conservation of energy and calculate the potential energy at the maximum height attained by the stone. (g = 10 m/s2)
ii) Using the same principle, state what will be the total energy of the body at its half-way point?
Mass of the stone, m = 64.0 g;
Initial speed with which the stone is thrown, v = 20 m/s
Potential energy at top = K.E at ground
ii) Total energy of the stone would remain the same. i.e., 12.8 J
A body of mass 1.50 kg is dropped from the second floor of a building which is at a height of 12 m. What is the force acting on it during its fall? ( g = 9.8 m/s2)
Using the formula,
F = mg
= 1.5 x 9.8
= 14.7 N