Is it true or false that air pollution only occurs as a result of human activity
2 answers:
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Answer:
a)
b)
c)
d)
e) Since Dave starts from house and finally returns to the house so displacement is zero.
Explanation:
Given:
- distance between the house and the store,
- speed of driving from house to store,
- speed of driving back from store to house,
Since the store is located towards east from his house and the velocity in this direction is taken negative and contrary to this the velocity in the west direction is taken positive.
a)
time taken in reaching the store:
b)
Now the time taken in returning form the store:
therefore total time taken by the trip:
c)
the time taken by the trip in minutes:
d)
distance travelled in the whole trip:
e)
Since Dave starts from house and finally returns to the house so displacement is zero.
Answer:
the height at which the limestone cube must be placed is 0.23 m.
Explanation:
Given;
mass of limestone cube, m₁ = 0.1 kg
initial velocity of the limestone cube, u₁ = 0
mass of steel cube, m₂ = 0.2 kg
initial velocity of the steel cube, u₂ = 0
final velocity of the steel cube, v₂ = 1.5 m/s
Apply the principle of conservation of energy to determine the height of the limestone cube.
Potential energy of the limestone cube at top = Kinetic energy of steel cube at base
m₁gh = ¹/₂m₂v₂²
where;
h is the height at which the limestone cube is placed
Therefore, the height at which the limestone cube must be placed is 0.23 m.