Science MCQs

A magnet can attract iron nails without touching them making it a non-contact force.

The chemical energy from food is converted into mechanical energy for muscular force.

The force exerted by machines like a crane is known as mechanical force.

The action is the book's weight pushing down on the table. The reaction is the table pushing back up on the book with an equal force.

The standard SI unit for measuring mass is the kilogram (kg).

The value of 'g' changes with altitude and depth and it is a property of the Earth's gravitational field not the object's shape.

Average speed for equal distances is the harmonic mean: 2*40*60/(40+60) = 4800/100 = 48 km/h.

The gun exerts a force on the bullet (action) and the bullet exerts an equal and opposite force on the gun (reaction) causing recoil.

The Sun's gravitational pull on Earth acts across the vacuum of space making it a non-contact force.

First convert mass to kg: 500 g = 0.5 kg. w = m * g = 0.5 kg * 10 N/kg = 5 N.