Explanation

Explanation

Friction can be reduced by changing from sliding to rolling.

Replace sliding friction with rolling element friction.

Such as with the use of rolling element bearings.

Explanation

Pressure exerted by the material on a smooth surface is not a factor affecting the resistance of a material.

The resistance is influenced by the type of material, temperature, and cross-sectional area.

Explanation

Watts are defined as 1 Watt = 1 Joule per second (1W = 1 J/s)

1 kW = 1000 J/s. 

Additional Information:

The SI Unit of power is Watt.

1 Watt = 1 Joule/second.

1 Joule = 1 Newton-meter

1 Watt = 1 Newton=meter/second

NA21-8-2023

Explanation

Explanation

Lead is commonly used as a shield against gamma rays.

Due to its high density.

It effectively absorbs and blocks gamma radiation.

Explanation

A rain gauge is a meteorological instrument to measure the precipitating rain in a given amount of time per unit area.

The instrument consists of a collection container that is placed in an open area.

Explanation

A dull black surface absorbs maximum radiation because it doesn’t reflect or transmit light.

Such surfaces are used in experiments and devices like blackbody radiators for accurate heat absorption.

Explanation

Formula:

Gravitational Potential Energy (GPE) = m × g × h

Where:

m = mass = 12 kg

g = gravitational acceleration = 9.8 m/s²

h = height = 5 m

GPE = 12 × 9.8 × 5 = 588 J

Explanation

The center of gravity is the point where the entire weight of an object appears to act.

It can lie inside or outside the object, depending on its shape (e.g., outside for a ring or hollow sphere).