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withABHISHEK K RB.Tech - Aerospace, Alliance UniversityCBSE Expert | Inventor of RocketPro6+ Years Teaching Exp | Mentored more than 5000 students
Kinematics 1D: Lecture 2
Kinematics
1D 3D2D
Distance
Displacement
Speed
Velocity
Acceleration
Kinematics
1D 3D2D
Distance
Displacement
Speed
Velocity
Acceleration
Consider a cube where the distance covered by a fish is as shown. Find the shortest distance between A and B.
A
B
Kinematics
1D 3D2D
Distance
Displacement
Speed
Velocity
Acceleration
Average Speed
Instantaneous Speed
Average Velocity
Instantaneous Velocity
The ratio of distance covered by a particle and time is called average speed
Average Speed
Place A Place B
12
3
6
9
1
2
457
8
10
11 vavg
= total distancetime
CLOCK Speed is a scalar quantityIn M.K.S. = m/sec. In C.G.S.= cm/sec.Dimension [M0LT-1]
The rate of distance covered by a particle is called instantaneous speed
Instantaneous Speed
Place A Place B
12
3
6
9
1
2
457
8
10
11 vinst
= dxdt
CLOCK
Speed is a scalar quantityIn M.K.S. = m/sec. In C.G.S.= cm/sec.Dimension [M0LT-1]
It is the ratio of total displacement to the total time taken.
=
Average velocity
Place BPlace A
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3
6
9
1
2
457
8
10
11
x1
x2
t2 – t
1
, t1 , t
2
=
Δt
is defined as Rate of change of displacementInstantaneous Velocity
12
3
6
9
1
2
457
8
10
11
Place BPlace A
Clockvelocity is a vector quantity
In M.K.S. = m/sec. In C.G.S.= cm/sec.Dimension [M0LT-1]
Instantaneous speed
Q1. A car is moving along a straight line, say OP in figure. It moves from O to P in 18 s and returns from P to Q in 6.0 s. What are the average velocity and average speed of the car in going (a) from O to P ? (b) from O to P and back to Q
Level 1
Q2. The position of an object moving along x–axis is given by x = a + bt2 where a = 8.5 m, b = 2.5 m s–2 and t is measured in seconds. What is its velocity at t = 0 s and t = 2.0 s. What is the average velocity between t = 2.0 s and t = 4.0 s ?
Level 2
Q3. A bird flies north at 20 m/s for 15 s. It rests for 5 s and then flies south at 25 m/s for 10 s. For the whole trip, find
(a) the average speed; (b) the average velocity
Level 1
Q4. If a car covers 2/5th of the total distance with v1 speed and 3/5th distance with v2 then average speed is
Level 2
Q5. A car moving on a straight road covers one third of the distance with 20 km/hr and the rest with 60 km/hr. The average speed is
Level 2
Q6. A particle located at x = 0 at time t = 0, starts moving along the positive x-direction with a velocity v that varies as 𝛂√x The displacement of the particle varies with time as
AIEEE - 2006
Q7. In 1.0 s, a particle goes from point A to point B, moving in a semicircle (as shown in the figure). The magnitude of the average velocity is
JEE ADVANCED
Q8. A particle moving in a straight line covers half the distance with speed of 3 m/s. The other half of the distance is covered in two equal time intervals with speed of 4.5 m/s and 7.5 m/s respectively. The average speed of the particle during this motion is
JEE ADVANCED
Q9. A body covers first one-third of the distance with a velocity 20 ms–1, the second one-third with a velocity of 30 ms–1 and last one-third with a velocity of 40 ms–1. The average velocity is nearly
JEE ADVANCED
