Physics

Friction and Inclined Planes

58 Questions

Friction and inclined plane problems focus on calculating forces, coefficients of static and kinetic friction, and motion on rough surfaces. Questions cover blocks on horizontal tables, angled planes, and simple harmonic motion systems. These physics concepts are strictly evaluated in engineering entrance and civil services tests.

Static friction coefficientKinetic friction forceInclined plane blocksDamped vibrations systemHorizontal table motion

Friction and Inclined Planes Questions

Multiple choice physics force and newton's laws of motion first law of motion newton's first law of motion momentum and newton's laws

A block is moved from rest through a distance of 4m along a straight line path.The mass of the block is 5 kg,and the  force acting on it is 20 N.If the kinetic energy acquired by the block be 40J,at what angle to the path the force is acting:

  1. $30^o$
  2. $60^o$
  3. $45^o$

  4. none of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
From work Energy theorem 
$ \triangle w = \triangle KE $ 
$ F.S = K.E $
$ F.S cos\theta = KE  $
$ cos\theta = \frac{KE}{FS} $
$ cos\theta = 1/2 $
$ \theta = 60^{\circ} $ 
Multiple choice physics along with motion what forces can do? force and it's unit force and its effects

An iron block of sides $50 cm\times 8 cm\times 15 cm$ has to be pushed along the floor. The force required will be minimum when the surface in contact with ground is

  1. $8 cm\times 15 cm $surface
  2. $50 cm\times 15 cm $surface
  3. $8 cm\times 50 cm $surface

  4. Force is same for all surfaces.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Force will be same for all the surfaces.
Hence, the correct option is $(D)$

Multiple choice physics the essence of change different forms of energy energy conversions energy transformations and energy transfers

A block of ice at 0 C whose mass is initially 50.0 kg slides along a horizontal surface starting at a speed of 5.38 m/s and finally coming of ice melted as a result of the friction between the block and the surface will be

  1. 2.16 g

  2. 4.0 g

  3. 1 g

  4. 50 g
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Initial KE = 0.5 * 50 * 5.38^2 = 723.6 J. Heat = 723.6 J. Mass melted = Heat / Latent heat = 723.6 / 334,000 J/kg = 0.00216 kg = 2.16 g.

Multiple choice chemistry substances in the surroundings - their states and properties measurement of density properties of substances fundamental and derived units

A rectangular block 5m x 4m x 2m lies on a table with its largest surface in contact with the table. The work done to keep it so that the block rests on the smallest surface is, if its density is 600 k $m ^ { - 3 }$

  1. $352800 \mathrm { J }$

  2. zero
  3. $376000 \mathrm { J }$
  4. $24,0000 \mathrm { J }$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The volume of Rectangular block $ = 5m \times 4m \times 2m$

$ = 40\,\,{m^3}$
Mass = Volume $ \times$ Density
$\begin{array}{l} =40\, \, { m^{ 3 } }\times 600\, \, k{ m^{ -3 } } \ =24,000=2.4\times { 10^{ 4 } }\, \, hg \end{array}$
Potential energy of block when it is lying on its largest surface $= mgh$
$ = 2.4 \times {10^4} \times 9.8 \times 1\,\,joule$
Potential energy of the block when it is lying on 
$ = mgh = 2.4 \times {10^4} \times 9.8 \times 2.5$
Work done = difference in potential energy
$\begin{array}{l} =\left( { 2.4\times { { 10 }^{ 4 } }\times 9.8\times 2.5-2.4\times { { 10 }^{ 4 } }\times 9.8\times 1 } \right) joule \ =2.4\times { 10^{ 4 } }\times 9.8\times 1.5\, \, joule \ =352800\, \, joule \end{array}$
Option A

Multiple choice physics force and newton's laws of motion momentum (p) introduction to momentum linear momentum

A body of mass $2 kg$ is sliding with a constant velocity of $4 m/s$ on a frictionless horizontal table. The net force required to keep the body moving with the same velocity is

  1. $8 N$
  2. $0 N$
  3. $4 N$
  4. $\dfrac { 1 }{ 2 } N$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

According to newton's first law of motion, an object either remains at rest or continues to move at a constant velocity, unless acted upon by an external net force.
Therefore The force required to keep the body moving with the same velocity is zero.

Multiple choice

What is the effect of wall friction on lateral earth pressure?

  1. It increases both active and passive earth pressure.

  2. It decreases both active and passive earth pressure.

  3. It increases active earth pressure and decreases passive earth pressure.

  4. It decreases active earth pressure and increases passive earth pressure.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Wall friction between the soil and the retaining wall reduces active earth pressure and increases passive earth pressure. This is because the friction between the soil and the wall resists the movement of the soil, reducing the active earth pressure and increasing the resistance to movement, which in turn increases the passive earth pressure.

Multiple choice

The coefficient of friction is a dimensionless quantity that represents the ratio of the force of friction to the normal force between two surfaces.

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The coefficient of friction is a property of the materials in contact and is independent of the area of contact.

Multiple choice

In a physics-based puzzle game, a player character pushes a crate with a mass of 50 kg across a horizontal surface with a coefficient of kinetic friction of 0.2. If the player applies a force of 100 N to the crate, what is the acceleration of the crate?

  1. 1.6 m/s^2

  2. 2.4 m/s^2

  3. 3.2 m/s^2

  4. 4.0 m/s^2
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The force of kinetic friction (F_k) is given by the equation: F_k = μ_k * N, where μ_k is the coefficient of kinetic friction and N is the normal force. Since the crate is on a horizontal surface, the normal force is equal to the weight of the crate: N = m * g, where m is the mass and g is the acceleration due to gravity. Plugging in the values, we get: F_k = 0.2 * 50 kg * 9.8 m/s^2 = 98 N. The net force acting on the crate is the force applied by the player minus the force of kinetic friction: F_net = 100 N - 98 N = 2 N. Using Newton's second law: F = m * a, where F is the net force, m is the mass, and a is the acceleration, we can calculate the acceleration of the crate: a = F_net / m = 2 N / 50 kg = 1.6 m/s^2.

Multiple choice

In a physics-based puzzle game, a player character pushes a crate with a mass of 50 kg across a horizontal surface with a coefficient of static friction of 0.4. If the player applies a force of 200 N to the crate, what is the acceleration of the crate?

  1. 2.4 m/s^2

  2. 3.2 m/s^2

  3. 4.0 m/s^2

  4. 4.8 m/s^2
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The force of static friction (F_s) is given by the equation: F_s = μ_s * N, where μ_s is the coefficient of static friction and N is the normal force. Since the crate is on a horizontal surface, the normal force is equal to the weight of the crate: N = m * g, where m is the mass and g is the acceleration due to gravity. Plugging in the values, we get: F_s = 0.4 * 50 kg * 9.8 m/s^2 = 196 N. Since the force applied by the player (200 N) is greater than the force of static friction, the crate will start moving. The net force acting on the crate is the force applied by the player minus the force of kinetic friction: F_net = 200 N - 196 N = 4 N. Using Newton's second law: F = m * a, where F is the net force, m is the mass, and a is the acceleration, we can calculate the acceleration of the crate: a = F_net / m = 4 N / 50 kg = 2.4 m/s^2.

Multiple choice

The coefficient of friction is a measure of the:

  1. Force required to move an object

  2. Resistance to motion between two surfaces

  3. Mass of an object

  4. Velocity of an object
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The coefficient of friction is a dimensionless quantity that characterizes the frictional interaction between two surfaces.

Multiple choice

The angle at which the coefficient of static friction is equal to the coefficient of kinetic friction is called the:

  1. Angle of repose

  2. Angle of incidence

  3. Angle of reflection

  4. Angle of deviation
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The angle of repose is the angle at which a loose granular material will come to rest on a slope.

Multiple choice

What is the relationship between the angle of internal friction ($\phi$) and the angle of repose ($\theta$) for cohesionless soils?

  1. $\phi$ =$\theta$
  2. $\phi$ <$\theta$
  3. $\phi$ >$\theta$
  4. $\phi$ is unrelated to$\theta$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

For cohesionless soils, the angle of internal friction ($\phi$) is typically less than the angle of repose ($\theta$) due to the influence of particle shape and surface roughness.