briefly explain about constant
acceleration
1. Distinguish between speed and velocity. (AS)
Reflections on concepts
0277
D4E5E4
3. How can you say that a body is in motion? Is it a common property?
4. Are average speed and average velocity same? If not explain why? (A
5. How do you measure instantaneous speed? (AS)
6. Explain acceleration with an example ? (AS)
Answers
Answer:
a)-The magnitude of displacement over an interval of time is the shortest distance (which is a straight line) between the initial and final positions of the particle
The total path length of a particle is the actual path length covered by the particle in a given interval of time.
For example, suppose a particle moves from point A to point B and then, comes back to a point, C (between A and B) taking a total time t, . Then, the magnitude of displacement of the particle = AC.
Whereas, total path length = AB + BC
b)-Magnitude of velocity =
time
Magnitudeofdisplacement
For given figure average velocityv=
t
AC
Average speed=
t
totalpath
S=
t
AB+BC
Since (AB + BC) > AC, average speed is greater than the magnitude of average velocity. The two quantities will be equal if the particle continues to move along a straight line.
(ii)
a) Time taken to reach market t
1
=
5
2.5
=0.5hour=30min
time taken to get back to home is t
2
=dfrac2.57.5=.33hour=20min
Average velocity for 0-30 in is v=
.5
2.5
=5km/h
Average speed for 0-30 in is s=
.5
2.5
=5km/h
total time he took for travelling t=30+20=50min=
6
5
hour
When he reached back then net displacement is zero
so for 0-50 min
Average velocity for 0-50 in is v=
6
5
0
=0km/h
Total distance he traveled when he arrive back is 2.5+2.5=5km
Average speed for 0-50 in is v=
6
5
5
=6km/h
Distance traveled in first 30 min is =2.5 km
distance traveled (while returning ) in 10 min is d=7.5×
6
1
=1.25km
Total time is 40 min or
3
2
So displacement in 0-40 min is 2.5−1.25=1.25km
Average velocity for 0-40 in is v=
3
2
1.25
=1.875km/h
Average speed for 0-40 in is v=
3
2
3.75
=5.625km/h
solution
Answer:
Constant acceleration means the velocity keeps on increasing constantly that is the increase in velocity per second is same. Also the direction of motion remains the same since acceleration is a vector quantity.
Whenever the speed of an object changes, that object is said to be accelerating. Acceleration is defined as the rate that your speed changes, or how fast your speed is changing. ... An object that travels with constant acceleration has a speed that changes by the same amount each second.