Tag: physics

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Questions Related to physics

Multiple choice physics force and newton's laws of motion concept of inertia galileo's law and inertia mass and inertia

Suppose gravity of earth suddenly becomes zero, then in which direction
will the moon begin to move if no other celestial body affects it ?

  1. Radial

  2. Tangential

  3. cant say

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

Moon will be launched in tangential direction with a speed at which it was orbiting around the earth.

In other words, it's speed and direction will be what it was at the time when gravitational force of earth ceased to exist.

Multiple choice physics force and newton's laws of motion concept of inertia galileo's law and inertia mass and inertia

Passengers standing in a bus are thrown outwards when the bus takes a sudden turn. This is due to:

  1. outward pull on them

  2. inertia

  3. change in momentum

  4. change in acceleration
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Newton's I law of inertia states that an object will change its direction when a force is applied to it. Hence, when a bus takes a sudden turn the passengers are thrown outward. This is due to the inertia of direction.

Multiple choice physics force and newton's laws of motion concept of inertia galileo's law and inertia mass and inertia

A truck and a car are moving with same kinetic energy. They are brought to rest by the application of brakes which provide equal force.

  1. both will cover equal distance

  2. the truck will cover a greater distance

  3. the car will cover a greater distance

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

We know that, ${u}^{2}=2as$    (as final velocity will be zero).

$\Rightarrow$ $s=m\dfrac{{u}^{2}}{2F}$.
truck has greater mass  so distance will be more for truck yhan the car.

Multiple choice physics force and newton's laws of motion concept of inertia galileo's law and inertia mass and inertia

Two balls of the same size but of different materials, rubber and iron are kept on the smooth floor of a moving train. The brakes are applied suddenly to stop the train. Will the balls start rolling? If so, in which direction? Will they move with the same speed? 

  1. Iron ball is faster than rubber ball

  2. Rubber ball is faster than iron ball

  3. Both move at the same speed

  4. None of them move
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

(a) Inertia is the name for the tendency of an object in motion to remain in motion, or an object at rest to remain at rest, unless acted upon by a force. This concept was quantified in Newton's First Law of Motion. For example when a car is abruptly accelerated, drivers and passengers may feel as though their bodies are moving backward. In reality, inertia is making the body want to stay in place as the car moves forward.

(b) Yes, both the balls will start rolling due to inertia of motion. The train stops due to brakes. But the balls continue to move in the direction of the train. But the balls will not roll with the same speed. Iron ball will move slower than the rubber ball because it is heavier in weight.

Multiple choice physics dynamics - explaining motion concept of inertia galileo's law and inertia mass and inertia

Galilee's law of inertia is another name for newton's (... ) law of motion.

  1. First

  2. Second

  3. Third

  4. Anyone of the above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Galileo's law of inertia is another name for newton's First law of motion. Newton's first law states that an object will remain at rest or move at a constant speed in a straight line unless it is acted on by an unbalanced force. Inertia comes from mass. Objects with more mass have more inertia.

Multiple choice physics dynamics - explaining motion concept of inertia galileo's law and inertia mass and inertia

What is the other name of Galileo's law of falling bodies?

  1. Law of motion

  2. Newton's first law

  3. Newton's second law

  4. Newton's third law
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Galelio’s hypothesis stated,”A falling body accelerates uniformly: it picks up equal amounts of speed in equal time intervals, so that, if it falls from rest, it is moving twice as fast after two seconds as it was moving after one second, and moving three times as fast after three seconds as it was after one second.”


Multiple choice physics dynamics - explaining motion concept of inertia galileo's law and inertia mass and inertia

The term inertia was first used by

  1. Newton

  2. Galileo

  3. Aristotle

  4. Kepler
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Galileo, a premier scientist in the seventeenth century, developed the concept of inertia. Galileo reasoned that moving objects eventually stop because of a force called friction. First thing it was discovered and not invented. It was discovered and stated and proved by Sir Isaac Newton.

Hence,
option $B$ is correct answer.

Multiple choice physics units and measurement: error analysis accuracy of measurement accuracy and precision accuracy, precision and uncertainty in measurement

The length of two rods measured by a meter scale are 60.0 cm and 20.0 cm respectively. The least count of meter scale is 1 mm. Then

  1. First measurement is more accurate

  2. Second measurement is more accurate

  3. Both measurement are equally accurate

  4. First measurement is more is more precise
Reveal answer Fill a bubble to check yourself
C,D Correct answer
Multiple choice physics units and measurement: error analysis accuracy of measurement accuracy and precision accuracy, precision and uncertainty in measurement

The time of 25 oscillations of a simple pendulum is measured to be $50.0 s$ by a watch of least count $0.1 s$. The percentage error in time is

  1. $0.2 \%$

  2. $0.02 \%$

  3. $0.002 \%$

  4. $2 \%$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The total time is 50.0 s with a least count of 0.1 s. The absolute error is 0.1 s. Percentage error = (absolute error / total time) * 100 = (0.1 / 50.0) * 100 = 0.2%.

Multiple choice physics units and measurement: error analysis accuracy of measurement accuracy and precision accuracy, precision and uncertainty in measurement

The error in the measurement of length of a simple pendulum is $0.1\%$ and error in the time period is $2 \%$. The possible maximum error in the quantity having dimensional formula $LT^{-2}$ is

  1. $1.1 \%$

  2. $2.2\%$

  3. $4.1\%$

  4. $6.1\%$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Given,

Error $\%$ in time $=2\%=\dfrac{2}{100}=\dfrac{1}{50}=2\%$
Error $\%$ in length $=1\%$
Find $\%$ error in $\dfrac{1}{12}$
$\therefore$ as $\dfrac{\triangle A}{A}=\left( \dfrac{\triangle 2}{2}\right) +\left( \dfrac{\triangle Q}{Q}\right)$    if $A=\dfrac{t}{Q}$
Thus, 
$\Rightarrow \%$ error $=\left( \dfrac{\triangle L}{L}\right) +2\left( \dfrac{\triangle T}{T}\right)$
                   $=\left( 2\%\right) +2\left( .1\%\right)$
                   $=2\%+.2\%$
                   $=2.2\%$
Hence, the answer is $2.2\%.$