mumtaz jarra (10)

MOTION
EXAMPLES
1.an object travels 16 m in 4 sce then
another 16 m in 2 sec. what is the average speed of the object ?
answer. total distance travelled =16 +16 =32 m
total time taken =4 s + 2 s = 6 s
average speed = total distance travelled
------------------------
total time taken
= 32 m
----
6s
= 5.33 m/s
example 2
question : the odometer of a car reads 2000 km at the start of a trip. and 2400 km at the end of the trip.if the trip took 8 h caculate the average speed ofvthe car in km/h nd m/ s
answer: distance covered = 2400 km - 2000 km = 400 km
time elapsed t = 8 hour
average speed = s 400 km
- = ------
t 8 h
= 50 km 1000 1h
-- * ---- * ---
h 1km 36
= 13.9 m/s
example 3.
question; usha swims in a 90 m long pool. she coverrs 180 m in one minute by swimming feomcend end to the othwe end to and bacj aling the same srraight path.find tge average velocity of usha.
anawer. displacment of usha in 1 min = 0 m
average speed =total distance covered / totalvtym taken
= 180 m = 180 m / 1min * 1 min / 60 sec
= 3 m/s
average velocity = displacment / total time taken
= 0 m / 60 s
= 0 m/s
question : define the scaler quantty and name the 5 physical quantytity which are scaker
answer : the physical quantities in which oonly magnitude is measured and direction is not mention
examples : speed , distance

question : an athelete completes one round of a circilar track of diameter 200 m in 40 aec.what will be the distance covered and the displacmebt atvthe end of 2 minutes 20 sec.
answer : diameter of circular path = 200 m
radius of circular path = 200 / 2 = 100 m
time taken by athelete = 40 sec
distance covered ( s ) = 2 * 22/7
= 2 *22 / 7 * 100
speed = (v) = distance / time
= 2 * 2200 / 7 * 40
= 4400/ 7 * 40
distance covered in 140 s = speed * tine
4400 / 7*40*
no of round in 40 sec = 1
no of round in 140 sec = 140'/ 40 = 3 1/2
dispalacment =200 mi
questipn : a motorboat strom rest on a lake accelatres in a straight line at a cobstabt rate of 3.0 m/aec for 8.0 swc .how far does the boatvtravel during this time