A) The vertical component of velocity v is taking the rock to a height
Vertical component =
The time taken to reach maximum height =
So total time of rocks flight =
Range of rock is due to the horizontal component of velocity =
Range =
=
Maximum height =
=
Since range = maximum height
We have
So when angle of projection is
range is equal to maximum height reached.
b) We have range =
=
Maximum of range is reached when
Maximum range =
c) For range to be equal to maximum height only condition is
, it does not depend upon acceleration due to gravity and velocity. That angle is a constant.
The
half-life of this radioactive isotope is 9 months for it decreases to
one-fourth its original amount in 18 months. Half-life means a certain length
of time after which half of the amount of radioactive element has decayed.
Therefore,
the half-life of this particular isotope is 18 months. After 18 months the
isotope was at one-half, then another 18 months, the isotope was at one-fourth,
which is 9 months where one-fourth is one-half of one half.
Answer:
3m/s²
Explanation:
final velocity - initial velocity
______________________ = Acceleration
elapsed time
Answer:
C. Both Technicians A and B
Explanation:
To loosen a fastener immediately especially if it is a rusted one we can follow these steps.
1. Tap the sides of the fastener so that the rust particle fall off.
2. These rust particles can be brushed off.
3. Spray the fastener with the penetrating oil.
4. Again tap the sides with a hammer to let the oil penetrate the inter-locked parts (threads in case of a nut and bolt).
5. Loosen the fastener after oil has penetrated.
Note: It should be kept in consideration that spraying alone won't do the job, tapping is essential to let the oil penetrate deep in to free the rusted parts.