Tag: introduction to simple machines

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

........ is defined as the ratio of the distance moved by effort and load, in the same time interval.

  1. Velocity ratio

  2. Mechanical advantage

  3. Both

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

Velocity ratio = $\displaystyle \frac { Distance\quad moved\quad by\quad the\quad effort }{ Corresponding\quad distane\quad moved\quad by\quad the\quad load } $
It only depends on the design of machine and is always same for a particular machine.

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

Efficiency is

  1. $\displaystyle \frac { Energy\quad input }{ Energy\quad output } \times 100$

  2. $\displaystyle \frac { mechanical\quad advantage }{ velocity\quad ratio } \times 100$

  3. Both

  4. None
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

As no machine is perfectly efficient.
So, we define efficiency as efficiency = $\displaystyle \frac { Energy\quad input }{ Energy\quad output } \times 100$
Also Efficiency = $\displaystyle \frac { mechanical\quad advantage }{ velocity\quad ratio } \times 100$
A petrol engine is about 30% efficient, a diesel engine is 40% efficient.

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

Akhil has to lift a load of $800N$ onto a platform of $2m$ height. Instead, he pushes the load up a ramp $4m$ long. Find the force required to lift the load vertically up.

  1. $200N$

  2. $600N$

  3. $400N$

  4. $800N$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The vertical force is the gravitational force means weight of the load. 

According to question, the weight of load is $mg=800 N$, this will be the required force to lift the load vertically.  

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

Which of the following statements is NOT correct?

  1. In a first order lever, the fulcrum is placed between the effort and the load

  2. The mechanical advantage of a second class levers is greater than $1$ as load is situated in between to effort and fulcrum.

  3. An inclined plane in a hospital, helps pushing a wheel chair easily.

  4. A crow bar is an example of second class lever
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

A crowbar is a classic example of a first-class lever, where the fulcrum is between the effort and the load. Therefore, stating it is a second-class lever is incorrect.