Class 9 Science : Practice Questions and Answers

Bacteria are prokaryotic cells that lack a membrane-bound nucleus.

The plasma membrane controls the movement of substances into and out of the cell.

The speed of sound in water is approximately 1500 m/s.

Sound waves are longitudinal because particles vibrate parallel to the direction of wave propagation.

A pendulum continuously converts kinetic energy into potential energy and back.

Energy consumed = Power × Time = 60 W × 2 h = 120 Wh.

Potential energy is stored energy due to position or configuration.

Work done is zero when there is no displacement.

Gravitational force acts between all objects that have mass.

Weight increases with mass because weight depends on gravitational force.

Gravitational force is always attractive between masses.

The acceleration due to gravity on Earth is approximately 9.8 m/s².

When a person pushes a wall, the wall pushes back with an equal and opposite force.

Newton's First Law explains inertia, which causes the body to resist changes in motion.

Newton's Second Law relates force, mass, and acceleration through F = ma.

An object is in motion if its position changes with time.

Motion along a straight path is called rectilinear motion.

The object returns to its starting point, so displacement is zero.

The SI unit of acceleration is meter per second squared (m/s²).

Acids are characterized by their sour taste and their ability to turn blue litmus red.