Online Test — Force and Laws of Motion
18 Questions • 15 min • Chapter MCQ
15:00
Question 1 of 18
The SI unit of force is the:
joule
newton
pascal
watt
Explanation: Force is measured in newtons ($\text{N}$).
Question 2 of 18
Balanced forces acting on a body produce a net force of:
maximum
zero
infinite
half
Explanation: When forces are balanced, the net force is zero.
Question 3 of 18
The tendency of a body to resist a change in its state of motion is called:
momentum
inertia
force
acceleration
Explanation: This property is inertia, measured by mass.
Question 4 of 18
Newton's First Law is also known as the law of:
gravitation
inertia
momentum
action
Explanation: It describes inertia, so it is the law of inertia.
Question 5 of 18
A passenger lurches forward when a moving bus stops suddenly because of inertia of:
rest
motion
direction
shape
Explanation: The body keeps moving forward — inertia of motion.
Question 6 of 18
The momentum of a body is given by:
$p = ma$
$p = mv$
$p = m/v$
$p = v/m$
Explanation: Momentum is mass times velocity, $p = mv$.
Question 7 of 18
The SI unit of momentum is:
$\text{N}$
$\text{kg m/s}$
$\text{m/s}^2$
$\text{J}$
Explanation: Momentum is measured in $\text{kg m/s}$.
Question 8 of 18
Newton's Second Law gives force as the:
product of mass and velocity
rate of change of momentum
change in displacement
rate of change of mass
Explanation: $F = \frac{\Delta p}{\Delta t}$, the rate of change of momentum.
Question 9 of 18
The momentum of a $2\ \text{kg}$ ball moving at $5\ \text{m/s}$ is:
$2.5\ \text{kg m/s}$
$7\ \text{kg m/s}$
$10\ \text{kg m/s}$
$0.4\ \text{kg m/s}$
Explanation: $p = mv = 2 \times 5 = 10\ \text{kg m/s}$.
Question 10 of 18
A $3\ \text{kg}$ body has an acceleration of $4\ \text{m/s}^2$. The force on it is:
$0.75\ \text{N}$
$7\ \text{N}$
$12\ \text{N}$
$1.33\ \text{N}$
Explanation: $F = ma = 3 \times 4 = 12\ \text{N}$.
Question 11 of 18
One newton is equal to:
$1\ \text{kg m/s}$
$1\ \text{kg m/s}^2$
$1\ \text{kg/s}$
$1\ \text{kg m}^2$
Explanation: $1\ \text{N} = 1\ \text{kg m/s}^2$.
Question 12 of 18
Action and reaction forces:
act on the same body
are unequal
act on two different bodies
always cancel out
Explanation: They act on two different bodies, so they do not cancel.
Question 13 of 18
The recoil of a gun is best explained by conservation of:
energy
momentum
mass
charge
Explanation: The bullet's forward momentum equals the gun's backward momentum.
Question 14 of 18
A rocket moves forward by ejecting gases:
upward
downward
sideways
forward
Explanation: Gases pushed downward push the rocket upward (Third Law).
Question 15 of 18
For a fixed force, increasing the mass of a body will:
increase acceleration
decrease acceleration
not change acceleration
make it infinite
Explanation: $a = F/m$, so larger mass gives smaller acceleration.
Question 16 of 18
A cricketer pulls his hands back while catching a ball to:
increase the force
increase the momentum
increase contact time and reduce force
increase the ball's speed
Explanation: Longer contact time reduces force since $F = \Delta p/\Delta t$.
Question 17 of 18
A $2\ \text{kg}$ trolley at $3\ \text{m/s}$ sticks to a $1\ \text{kg}$ stationary trolley. Their common velocity is:
$1\ \text{m/s}$
$2\ \text{m/s}$
$3\ \text{m/s}$
$6\ \text{m/s}$
Explanation: $2 \times 3 = 3v \Rightarrow v = 2\ \text{m/s}$.
Question 18 of 18
Mass of a body is a measure of its:
momentum
inertia
force
weight only
Explanation: Greater mass means greater inertia.