i. A body has translatory motion if it moves along a
In Translatory or Translational motion, a body moves along a line without any rotation. The line may be straight or curved. For example, a car moving in a straight line has translational motion. Similarly, an aeroplane moving straight in translation motion.
ii. The motion of a body about its axis is called ?
The spinning motion of a body about its axis is called rotatory motion. The motion of wheel, motion of a top, the motion earth about its geographic axis that causes day and night are the example of rotatory motion.
iii. Which of the following is a vector quantity?
Displacement is a vector quantity because it has both magnitude and direction. While speed, distance and power are scalar quantity, having only magnitude and giving no information about direction.
iv. If an object is moving with constant speed then its distance-time graph will be a straight line.
As distance = speed x time. And when speed is constant the straight line will pass diagonally from the origin which means it is inclined to the time axis.
v. A straight line parallel to time-axis on a distance-time graph tells that the object is
The object at rest means that the distance moved by the object with time is Zero. Thus a horizontal line parallel to time axis on a distance-time graph shows the speed of the object is zero.
vi. The speed-time graph of a car is shown in the figure below, which of the following statements is true?
As Acceleration = slope of the line of the given figure = v/t. Here, velocity v = 15 ms^-1, t=10s, Thus Acceleration "a" = 15 /10 = 1.5 ms^-2.
vii. Which of the following graph is representing uniform acceleration ? :
Figure (a) shows that the speed of an object is uniformly changing i.e speed changing at constant rate. It means that body is moving uniform acceleration. So for uniform acceleration speed-time graph would be straight line.
viii. By dividing displacement of a moving body with time, we obtain
Velocity is the rate of change of displacement with time. Simple velocity equation: velocity = distance / time
ix. A ball is thrown vertically upward. lts velocity at the highest point is:
When a ball is thrown vertically upward against the gravitational pull of the earth. the speed of the ball decrease gradually with time and at the highest point it become zero because the ball comes at rest and then continue its downfall.
x. A change in position is called:
Position means the location of a certain place or Object from a reference point. so the actual path length between two positions is called distance.
xi. A train is moving at a speed of 36 kmh^-1. Its speed expressed in ms^-1 is
36 km/h (1 km = 1000 m & 1 h = 3600 s)= 36 x1000 m / 3600s =10 m/s.
xii. A car starts from rest. It acquires a speed of 25 ms^-1 after 20s. The distance moved by the car during this time is:
Here we will solve this problem by Second's Equation of Motion S = Vit + (1/2) a t² for that we first to find Acceleration a = (Vf - Vi)/t = 1.25 m/s². Now by 2nd Eqn of Motion S = 250 m.
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