These questions are useful for the practice for the candidates going to appear for JEE Main Examinations (New Pattern exam for admission to IITs, NITs and IIITs). The questions are from Physics Subject. The questions test the comprehensive skills of the candidates. Answers are also given at the end of the questions.
A particle starts from rest with a time varying acceleration a = (2t-4). Here t is in seconds and a in m/s2. The particle moves along x-axis.
1. Particle comes to rest after a time t = …….. second
A) 1 B) 4 C) 3 D) 2
2. Maximum speed of the particle while moving in negative X-direction is at t = ……. second
A) 3 B) 4 C) 2 D) 1
3. The velocity time graph of the particle is ….
A) parabola passing through origin
B) straight line not passing through origin
C) parabola not passing through origin
D) straight line passing through origin
COMPREHENSION – 4
It is known that if a steel ball and a feather are dropped from the same height, the steel ball falls faster than the feather. The following scientists have two different views on falling bodies.
Scientist 1 :
The force of gravity makes things fall. The greater the gravitational force on an object, the faster it falls. The steel ball falls faster because it is more massive than the feather, and thus is attracted more strongly by the earth’s gravitational field.
Scientist 2 :
The mass of an object does not determine how fast an object falls, but shape does. Two identical pieces of paper will fall at different speeds, if one of them is crumpled into a small ball. That is because gravity is not the only force acting on a falling object. Air buoys up objects falling through it. Since the shape of the steel ball gives it less air resistance than a feather, it falls faster.
4. According to Scientist 1, the property that determines how fast an object will fall is its
A) chemical composition B) mass C) shape D) gravity
5. Suppose a small ball and a feather having the same weight are dropped from the same height. Which of the following would Scientist 1 predict?
A) The feather would fall faster than the ball
B) The ball and feather would fall at the same speed
C) The ball would fall faster than the feather
D) None of the above
6. Both scientists agree that the rate which an object falls is affected by the
A) force of gravity
B) mass of the object
C) object’s resistance of air
D) shape of object
KEY: 1.B 2.C 3.A 4.B 5.B 6.A