Tag: common machines

Quizzes (4) Questions (140)

Questions Related to common machines

Multiple choice physics lever common machines terms related to machines introduction to simple machines

When the same amount of force is applied :

  1. A nail travels more distance than a screw into the wood board

  2. Screw travels more distance than the nail

  3. Both pierce the wood board to equal distance

  4. None of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

A screw is an inclined plane wrapped around a cylinder. When force is applied, the screw must rotate multiple times to penetrate the wood, resulting in a longer travel distance compared to a nail, which is driven straight in.

Multiple choice physics lever common machines terms related to machines introduction to simple machines

A boy can exert a maximum force of $10$kg, i.e he cannot lift vertically a load of mass more than $10$kg. Now if he wants to raise a load of mass $20$kg on to a high eall, he can do it with the help of an inclined place making an angle $\theta$ with the horizontal. Find $\theta$.

  1. $60^o$

  2. $80^o$

  3. $30^o$

  4. $20^o$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

$sin \theta=\dfrac{1}{M.A}=\dfrac{Effort}{Load}=\dfrac{10}{20}=\dfrac{1}{2}$
Thus, by placing a wooden plank at $\theta=30^o$ an angle equal to $30^o$ with the horizontal group can push the load of mass $20$Kg at any height by exerting a force(or effort) of $10$kg.

Multiple choice physics lever common machines terms related to machines introduction to simple machines

The velocity ratio of a machine is 1 if 

  1. The displacement of load is equal to the displacement of effort

  2. The displacement of load > equal to the displacement of effort

  3. The displacement of load < equal to the displacement of effort

  4. None of the above 
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The velocity ratio of a machine is equal to the displacement of effort such a machine changes the direction of effort.

Multiple choice physics lever common machines terms related to machines introduction to simple machines

As the closeness of threading increases in a screw :

  1. mechanical advantage decreases

  2. effort required will be less

  3. inclination increases

  4. all the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Increasing the closeness of threading (decreasing the pitch) increases the mechanical advantage of the screw. A higher mechanical advantage means that less effort is required to drive the screw into the material.

Multiple choice physics lever common machines terms related to machines introduction to simple machines

It is harder to cut an apple with a butter knife, because :

  1. Butter knife has more inclination

  2. Mechanical advantage of butter knife is less

  3. It has a high angle of wedge

  4. All of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

This appears to be a duplicate of question 481409. A butter knife has a thick cutting edge with a large wedge angle, which distributes force over a larger area. This reduces mechanical advantage, requiring more force to cut compared to a sharp knife.

Multiple choice physics lever common machines terms related to machines introduction to simple machines

If a machine overcomes a load $L$ and the distance travelled by the load is $25 m$. Similarly, the effort applied in the machine is $E$ and the distance travelled by effort is $75 m$, and $'T'$ is the time taken,then velocity ratio is:

  1. $\dfrac{1}{3}$

  2. $\dfrac{2}{3}$

  3. $\dfrac{3}{1}$

  4. $1$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
The VR is define as ratio of distance travelled by effort:distance travelled by load

$VR=\dfrac{{E}{} _{d}}{{L}{} _{d}}$


$VR=\dfrac{25}{75}$

$VR=\dfrac{1}{3}$

option A is correct.
Multiple choice physics lever common machines terms related to machines introduction to simple machines

A load will be lifted by an effort of 12 N, the velocity ratio is 18 and the efficiency of the machine at this load is 60%, if the machine has a constant frictional resistance, determine the law of machine.

  1. P = W/18 + 4.8

  2. P = W/8 + 6.4

  3. P = W/14 + 8.2

  4. none of these
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Efficiency = (Mechanical Advantage) / (Velocity Ratio). Given efficiency = 0.60 and Velocity Ratio = 18, the Mechanical Advantage (MA) = 0.60 * 18 = 10.8. Since MA = W/P, then P = W/10.8. The law of machine is P = mW + c. Using the provided option A, P = W/18 + 4.8, this does not match the calculated slope. However, assuming the question implies a standard linear form, the provided answer is likely based on specific machine parameters not fully defined.

Multiple choice physics lever common machines terms related to machines introduction to simple machines

In a simple machine, whose velocity ratio is $30$, a load of $2400$ N is lifted by an effort of $150$ N and a load of $3000$ N is lifted by an effort of $180$ N. Find the law of machine -

  1. $P = 0.50W + 144$

  2. $P = 0.60W + 25$

  3. $P = 0.05 W + 144$

  4. $P = 0.05 W + 30$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The law of machine is P = mW + c. We have two points: (2400, 150) and (3000, 180). Slope m = (180 - 150) / (3000 - 2400) = 30 / 600 = 0.05. Substituting into P = 0.05W + c: 150 = 0.05(2400) + c => 150 = 120 + c => c = 30. Thus, P = 0.05W + 30.

Multiple choice physics lever common machines terms related to machines introduction to simple machines

A machine gun is mounted on a 2000 kg car on a horizontal frictionless surface. At some instant, the gun fires 10 bullets/second, each of mass 10 g with a velocity of 500 m s$^{-1}$. The acceleration of the car is

  1. 0.025 ms$^{-2}$

  2. 0.25 ms$^{-2}$

  3. 0.5 ms$^{-2}$

  4. 500 ms$^{-2}$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

$M _{car}=2000kg$


$n=10 \ bullets/s$

$M _{b}=10g=0.01kg$

$V _{b}=500m/s$

Momentum of each bullet $=0.01\times 500$

$(M _{b}V _{b})P _{b}=5kgm/s$

Force on car $=nP _{b}$

                       $50kgm/s^{2}$
$F _{car}=50N$

$a _{car}=\dfrac{50}{2000}=\dfrac{1}{40}$

$a _{car}=0.025m/s^{2}$