2.1 Mention the various methods of inter-crop hybridisation. Which type of farming
system yields healthier grains?
0.2 Why does air pollution increase during winter? Explain how air moves over sea and land
during day and night.
0.3 Mention the elements and the ratio by mass of elements present in:
(a) Ammonia, (b) Carbon dioxide
Q.4 identify the energy involved in the following activities.
a. Winding a key in a toy, b. A running fast bowler, c. A stretched bow
Q.5 Differentiate between the following:
a. Acceleration due to gravity and gravitational force
b. Buoyancy and upthrust
0.6 Although there is huge increase in carbon dioxide production by various human activities,
the atmospheric carbon dioxide level is amounted in small quantities like around 409
parts per million. Explain the situation and its consequences.
0.7 a. There is a change in velocity observed from 10 m/s to 15 m/s when a force of 300 N is
applied on a body. Calculate the mass of the body?
b. What would be the force required to accelerate the speed of a vehicle weighing 1500 kg
and moving at a speed of 10 ms-2?
Answers
Answer:
Explanation:
Types of Hybridization:
Intervarietal Hybridization: The parents involved in hybridization belong to the same species; they may be two strains, varieties or races of the same species. ...
Distant Hybridization: This includes crosses between different species of the same genus or of different genera
0.2At night both land and sea cool down but water cools slower than land. The air above the water is warmer than the air above the land surface, and it rises up creating a region of low pressure above sea. So, wind current moves from the land towards sea during night.
0.3No. Compounds Chemical formula Ratio by mass of the combining elements
(a) Ammonia NH3 =14:3
(b) Carbon monoxide CO= 3:4
0.41) mechanical energy
2) motion energy
3) gravitational energy
4) elastic energy
0.5Every object in the universe exert gravitational pull to other objects. When the gravitational pull is exerted by Earth it is call Gravity. So gravity is the pull by earth. Whereas acceleration due to gravity is acceleration by which any object cmes towards the earth within its gravitational field.
0.7 a.It is gn that
u=10m/s
v=15m/s
F=300N
We have to find the mass of the object
F=m (v-u)
300=m (15-10)
m=300/5
=60 kg
b.According to Sir Isaac Newton's Second Law of Motion,
Force
(
F
)
=
Mass
(
m
)
×
Acceleration
(
a
)
.
∴
F
=
m
a
.
∴
F
=
(
2
k
g
)
×
(
3
m
s
2
)
.
∴
F
=
6
k
g
m
s
2
=
6
Newton.
=
6
N
.
Therefore, Force required to accelerate the body is
6
N
.
(answer).
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