Motion Test - 1

A century is a period of 100 years. Centuries are numbered ordinally in English and many other languages. The word century comes from the Latin centum, meaning one hundred. Century is sometimes abbreviated as c.

When an object moves along a circular path, it is called circular motion. During such a motion, the direction of motion at any point is given by the tangent at that point which changes continuously.

The length of the wooden box = Difference between the reading at both the ends

= 4.7−1.5 = 3.2 cm

Raju covers a longer distance with a higher speed as compared to Prem.

Displacement of the cyclist = Shortest distance between P and Q

= PO+OQ = a+a = 2a

Motion of soldiers on march past is rectilinear motion; Every oscillatory motion is also a periodic motion; Hockey player running after a ball is random motion.

A motion that repeats itself after equal intervals of time is known as periodic motion. Examples of periodic motion are a tuning fork or motion of a pendulum if you analyze the motion you will find that the pendulum passes through the mean position only after a definite interval of time. 

A bird fly in the sky is Non -Uniform motion because it travel unequal distance in equal interval of time.

Ton, unit of weight in the avoirdupois system equal to 2,000 pounds (907.18 kg) in the United States (the short ton) and 2,240 pounds (1,016.05 kg) in Britain (the long ton). The metric ton used in most other countries is 1,000 kg, equivalent to 2,204.6 pounds avoirdupois.

Motion of a vehicle on a straight road is not rectilinear motion.

Rotational Motion

When an object turns (or spins) about a fixed axis, it is called rotational motion.

For example: The motion of a spinning top ,the spinning of earth on the axis, turning of the blades of a fan, rotation of a wind mill or phirki, turning of a ball, turning of the hands of watch, turning of potter's wheel, turning of a bicycle wheel.

In case of collision, changes are most likely to be appear in the speed and direction of both the balls.

'Movement of a person on the road' is not an example of rotational motion.

The rotational motion of a body about its center of mass is called attitude dynamics. 

Given:

Distance = 45 metres.

Time = 9 seconds

To find:

Average speed in km/hr

Definitions:

Average speed is the ratio of total distance to the total time taken to cover that distance.

Calculation:

Speed = distance/time

⇒ Speed = 45/9

⇒ Speed = 5 m/s

Conversion:

We have to convert speed from m/s to km/hr :

5 m/s = 5 × (18/5) = 18 km/hr.

Rahul takes path XOY and Ravi takes path XY. Displacement is minimum distance between initial and final point = XY.

Rahul and Ravi both cover different distances XOY and XY respectively at the same time. Rahul covers more distance than Ravi in the same time. Hence Rahul covers longer distance with a higher speed.

P = 2.1 cm; Q = 3.0 cm; R = 3.1 cm; S = 2.5 cm

Average length of these sticks \(=\frac{P+Q+R+S}{4}=2.6 \mathrm{cm}\)

Quintal is not used as a unit for measuring length.

A car covers a distance of first \(=40 \frac{k m}{h r}\)

A car covers a distance of second hour \(=50 \frac{\mathrm{km}}{\mathrm{hr}}\)

Averrage Speed \(=\frac{2 A B}{A+B}\)

\(=\frac{2(40)(50)}{40+50}\)

\(=\frac{80(5)}{9}\)

\(=44.44 \frac{\mathrm{km}}{\mathrm{hr}}\)

Hence, this is non-uniform type of motion.

Initial volume of water in the cylinder, (before the immersion of the object) V₁ = 70cm³ Final volume in the cylinder (after the immersion of the object) V₂ = 82cm³

Hence, volume of the object immersed in the cylinder = Final volume - Initial volume = 82 cm³−70 cm³ = 12 cm³

FPO is not a system of measurements.

One gram has been divided into 1000 equal parts, each part is equal to One milligram.

The motion in which all the particles of a body move through the same distance in the same time is called translatory motion. There are two types of translatory motions: rectilinear motion; curvilinear motion.

1dm = 10²dam

When a body moves from one position to another, the shortest distance measured between the initial and the final positions of the moving body in a particular direction is called displacement. The actual length of the path travelled by a moving body in a given interval of time is called the distance travelled by that body. So displacement of a body may be zero, though distance can be finite. For example, in case of circular motion if the body comes back to its initial position then distance travelled is finite but displacement is zero.

As 20 divisions = 1 cm

\(\therefore \quad 1\) division \(=\frac{1}{20} \mathrm{cm}=0.05 \mathrm{cm}\) \(=0.5 \mathrm{mm}\)

Hence, least count of this scale = 0.5 mm

Motion of strings of a guitar shows oscillatory as well as vibratory motion.

Circular motion is the motion of an object that moves at a fixed distance from a fixed point. Here all objects rotate in circular motion.

The property of a body by virtue of which it resists any change in its state of rest or of motion in a straight line on its own is called its inertia.

20 seconds is equal to 1/3 minute.

1 minute  = 60 second

20 second = 20/60 th part of a minute

∴ 20 sec = 1/3th part of a minute.

Length of the thread placed on scale = 13.5 cm

As thread is folded 6 times,

∴ Length of the thread = 13.5×6 cm = 81 cm = 0.81 m

A decimeter is a unit of length in the metric system. The term “Deci” means one-tenth, and therefore decimetre means one-tenth of a meter. Since a meter is made up of 100 cm, one-tenth of 100 cm is 10 cm. Thus one decimeter measures 10 cm.

1 dm = 10 cm

Therefore, 100 dm = 100 × 10

= 1000 cm

A rider on horse falls back when horse starts running, all of a sudden because the rider is in state of rest initially and later inertia of rest keeps the upper part of body at rest while lower part of the body moves forward with horse.

Keep your eye vertically above the point where the measurement is to be taken.

Only (ii) shows the periodic as well as oscillatory motion. It is showing to and fro as well as motion which is repeating after regular time interval.