What are scalar and vector quantities? Define Newton's first law of motion. Calculate the resultant of two like parallel forces of 15N each.

The forces are like parallel forces, meaning they act in the same direction.

For like parallel forces, the resultant force is the sum of the individual forces.

The resultant force is 30 N in the direction of the forces.

Q.No:4 Calculate the spring constant for a spring which extends by a distance of 3.5cm when a load of 14N is hung from its end.

Force applied, $F = 14 \text{ N}$
Extension of the spring, $x = 3.5 \text{ cm}$

Hooke's Law states $F = kx$.
Rearranging for $k$:

The spring constant is 400 N/m.

Q.No:5 Define the term pressure and write down the S.I unit of pressure.

• Pressure is defined as the force exerted perpendicularly per unit area on a surface.
• The S.I. unit of pressure is the Pascal (Pa), which is equivalent to one Newton per square meter ($\text{N/m}^2$).

Q.No:6 Why weight of an object does not remain same everywhere on earth?
The weight of an object is the force of gravity acting on it, given by the formula $W = mg$, where $m$ is the mass and $g$ is the acceleration due to gravity. The mass of an object is constant, but the value of $g$ varies slightly across the Earth's surface. This variation is due to factors such as altitude (distance from Earth's center), latitude (Earth's equatorial bulge), and local geological variations, causing an object's weight to differ slightly from one location to another on Earth.

Q.No:7 Write a note on non-renewable energy sources.
Non-renewable energy sources are natural resources that exist in finite quantities and are consumed much faster than they can be naturally replenished. Once used, they are depleted and cannot be replaced on a human timescale. The primary examples include fossil fuels (such as coal, petroleum, and natural gas), which are formed from the remains of ancient organisms over millions of years, and nuclear fuels (like uranium), which are mined from the Earth.

Q.No:8 2 kg of copper requires 2050J of heat to raise its temperature through $10^\circ \text{C}$. Calculate the heat capacity of the sample.

Mass of copper, $m = 2 \text{ kg}$
Heat absorbed, $Q = 2050 \text{ J}$
Change in temperature, $\Delta T = 10^\circ \text{C}$

Heat capacity is defined as the amount of heat required to raise the temperature of an entire sample by one degree Celsius (or Kelvin).

The heat capacity of the copper sample is 205 J/^\circC.