Physics-DPP-3-Kinematics

PHYSICS Topic: KINEMATICS Date: 1. An elevator in which a man is standing is moving upwards with a speed of 10 m/sec. If the man drops a coin from a height of 2.45 metre, it reaches the floor of the elevator after a time : (g = 9.8 m/sec2) (b) s (c) 2 s (d) 1 s 2 2. If the velocity of a particle is given by v = (180 – 16x) 1/2 m/s then its acceleration will be : (a) zero (b) 8m/s2 (c) – 8m/s2 (d) – 4m/s2 3. A body is projected with a velocity u. If passes through a certain point above the ground after t1 sec. The time after which the body passes through the same point during the return journey is : u 2 ÷ æç u ö÷ æçu2 ö÷ æçu2 ö÷ (a) èç g – t1 ø÷ (b) 2çè g – t1 ø÷ (c) 3çè g – t1 ø÷ (d) 3ç g 2 – t1 ø÷ 4. An express train is moving with velocity v1 , meanwhile the driver of this train comes to know that an another train is also moving ahead with a velocity v2 on the same track. To void collision the driver applies retardation a. Then what will be the minimum time to void collision : v2 – v2 1 æv – v ö (a) t = v1 – v2 (b) t = 1 2 (c) t = ç 2 1 ÷ (d) none of these a 2 2 çè a ø÷ 5. A particle starts moving in a straight line with a constant acceleration a. At a time t1 seconds after the beginning of motion, the acceleration changes sign, remaining the same in magnitude. Determine the time from the beginning of motion, till it returns to the starting point : (a) t1 (2 + 2)sec (b) t2 (1 + 2)sec (c) t1 2 sec (d) 2 2 t1 sec 6. In the one-dimensional motion of a particle, the relation between position x and time t is given by x2 + 2x = t Choose the correct statement : (a) The retardation of the particle is 1 4(x + 1)3 (b) The uniform acceleration of the particle is 1 (x + 1)3 (c) The uniform velocity of the particle is 1 (x + 1)3 (d) The particle has a variable acceleration of 4t + 6. 7. A body freely falling from rest has a velocity v after it falls through distance h. The distance it has to fall down further for its velocity to become double is : (a) h (b) 2h (c) 3h (d) 4h 8. An object starts from rest at t = 0 & accelerates at a rate given by a = 6t then its velocity & displacement after 2 seconds will be (a) 10 m/sec, 8 m (b) 12 m/sec, 4 m (c) 4 m/sec, 6 m (d) 12 m/sec, 8 m PHYSICS Topic: KINEMATICS Date: Answer Key 1. (b) 2. (c) 3. (b) 4. (a) 5. (a) 6. (a) 7. (a) 8. (d)

Comments

Post a Comment

Popular posts from this blog

Planning to start your own coaching institute for JEE, NEET, CBSE or Foundation? Here's why not to waste time in developing study material from scratch. Instead use the readymade study material to stay focused on quality of teaching as quality of teaching is the primary job in coaching profession while study material is secondary one. Quality of teaching determines results of your coaching that decides success & future of your coaching while good quality study material is merely a necessary teaching aid that supplements your teaching (video in Hindi)

Image
Read more

Physics-30.24-Physics-Solids and Semiconductors

UNIT 24 - SOLIDS AND SEMICONDUCTORS 1. SOLID STATE ELECTRONICS (SEMICONDUCTORS) (A) Energy bands in solids: (i) In solids, the group of closely lying energy levels is known as energy band. (ii) In solids the energy bands are analogous to energy levels in an atom. (iii) In solids the atoms are arranged very close to each other. In these atoms there are discrete energy levels of electrons. For the formation of crystal these atoms come close together, then due to nucleus-nucleus, electron-electron and electron-nucleus interactions the discrete energy levels of atom distort and consequently each energy level spits into a large number of closely lying energy levels. (iv) The number of split energy levels is proportional to the number of atoms interacting with each other. If two atoms interact then each energy level splits into two out of which one will be somewhat above and another will be somewhat below the main energy level. In solids the number of atoms is very large ( 1023). Hence eac...
Read more

Physics-31.Rotational Mechanics

5.1 DEFINITION OF CENTRE OF MASS Centre of mass: Every physical system has associated with it a certain point whose motion characterizes the motion of the whole system. When the system moves under some external forces than this point moves as if the entire mass of the system is concentrated at this point and also the external force is applied at his point of translational motion. This point is called the centre of mass of the system. Centre of mass of system of n point masses or n particles is that point about which moment of mass of the system is zero, it means that if about a particular origin the moment of mass of system of n point masses is zero, then that particular origin is the centre of mass of the system. The concept of centre of mass is a pure mathematical concept. If there are n particles having mass m1, m2 ….m n and are placed in space (x1, y1, z1), (x2, y2, z2) ……….(x n, y n, z n) then centre of mass of system is defined as (X, Y, Z) where = Y = and Z = where...
Read more