1. Convert the following as directed
(a) 3720 seconds into minutes (b) 24 hours into seconds
(c) 1 year (365 days) into houm
2. A train, travelling at uniform speed takes 10 hours to cover a distance of 1200 km. Expressite
speed in km/h and m/s.
(Ans: 120 km/h, 33.3 m/s
3. A rocket travels at a speed of 15,000 m/s. Express this speed in km/h.
4. Amit's school bus travels at 36 km/h and Sushma's school bus travels at 11 m/s, whose school be
travels faster?
5. Show that 1 km/h = 5/18 m/s.
Answers
Explanation:
3720 seconds = 3.72 Minutes
24 hours = 24×60×60 = 86400 secs
1 year = 525600 mins
2. 120km/h , 2000m/s
3. 0.0041 km/h
4. Amit's school bus
Answer:
1:
a)3720secs into minute=3720/60mins
=62mins
b)24hrs into secs= 24*(60*60)secs
=24*3600secs
=86400secs
c)1year(365days) into hrs=24*365hrs
=8760hrs
2:
Total distance covered=1200km
Time taken by the train=10hrs
.·.Speed in km/hr=1200/10
=120 km/hr
Speed in m/s=(1200*1000)/(10*3600)
=1200000/36000
=33.3333333..m/s
3:
Speed of the rocket=15,000m/s
.·.Speed in km/hr=15000*3.6
=54000km/hr
4:
Speed of Amit's school bus=36km/hr
=36/3.6
=10m/s
Speed of Sushma's school bus=11m/s
·.·10m/s < 11m/s
.·.Sushma's school bus travels faster.
5:
We have,
RHS=5/18 m/s
Now,
LHS=1km/hr
=(1*1000)/(1*3600) m/s
=1000/3600 m/s
=10/36 m/s
=5/18 m/s
=RHS
Hence proved.