Maharashtra Board Class 11 Physics Solution Chapter 3 – Motion in a Plane
Balbharati Maharashtra Board Class 11 Physics Solution Chapter 3: Motion in a Plane. Marathi or English Medium Students of Class 11 get here Motion in a Plane full Exercise Solution.
|Maharashtra Class 11|
Motion in a Plane
1.) Choose the correct option.
i) An object thrown from a moving bus is on example of
(A) Uniform circular motion
(B) Rectilinear motion
(C) Projectile motion
(D) Motion in one dimension
An object thrown from a moving bus follows projectile motion.
ii) For a particle having a uniform circular motion, which of the following is constant
(A) Speed (B) Acceleration
(C) Velocity (D) Displacement
By definition of uniform circular motion it is the motion in which speed is constant.
iii) The bob of a conical pendulum under goes
(A) Rectilinear motion in horizontal plane
(B) Uniform motion in a horizontal circle
(C) Uniform motion in a vertical circle
(D) Rectilinear motion in vertical circle
The bob of a conical pendulum under goes uniform circular motion in horizontal motion.
iv) For uniform acceleration in rectilinear motion which of the following is not correct?
(A) Velocity-time graph is linear
(B) Acceleration is the slope of velocity time graph
(C) The area under the velocity-time graph equals displacement
(D) Velocity-time graph is nonlinear
For uniform acceleration in rectilinear motion Velocity-time graph is linear.
2.) Answer the following questions.
i) Separate the following in groups of scalar and vectors: velocity, speed and displacement, work done, force, power, energy, acceleration, electric charge, angular velocity.
Scalars- speed, work done, energy, power, electric charge.
Vectors- velocity, displacement, force, acceleration, angular velocity.
ii) Define average velocity and instantaneous velocity. When are they same?
Average velocity: This is defined as the displacement of the object to thethe time interval taken by object to complete the motion.
iii) Define free fall.
Answer- motion of body under only gravitational force is called free fall.
iv) If the motion of an object is described by x = f (t) write formulae for instantaneous velocity and acceleration.
For instantaneous velocity for motion x = f (t) is given by,
It can be seen from this equations that motion along x direction is completely controlled by x components of velocity and acceleration independent on y direction. While motion along y-direction is completely controlled by y-components of velocity and acceleration independent on x-direction. This shows that these two equations are independent of each other.
vi) Derive equations of motion graphically for a particle having uniform acceleration, moving along a straight line.
Consider velocity time graph shown in figure
1.) Consider an object traveling along AB at x=0 at t=0. Let initial velocity be u and at time t is v.
As slope of velocity time graph gives acceleration of motion hence Slope of line AB gives acceleration of motion. Thus,
viii) Show that the path of a projectile is a parabola.
Consider a body is projected with velocity u at an angle of θ as shown in figure. Then,
Horizontal component of ux= u x´sin (θ).
Vertical component of u, uy= u cos (θ).
This projectile motion is under gravitational acceleration only and it acts in vertically downward direction only hence
Acceleration on horizontal, ax=0
Acceleration on vertical, ay=−g
Using definition of velocity,
using law of motion for y direction as in y direction acceleration is constant.