Answer:
The bomb will remain in air for <u>17.5 s</u> before hitting the ground.
Explanation:
Given:
Initial vertical height is, 
Initial horizontal velocity is, 
Initial vertical velocity is, 
Let the time taken by the bomb to reach the ground be 't'.
So, consider the equation of motion of the bomb in the vertical direction.
The displacement of the bomb vertically is 
Acceleration in the vertical direction is due to gravity, 
Therefore, the displacement of the bomb is given as:

So, the bomb will remain in air for 17.5 s before hitting the ground.
Answer:
Explained
Explanation:
a) No, the keys were initially moving upward in the elevator only effects the initial velocity of the key and not the rate of change of velocity that is acceleration. So, the keys accelerate with the same acceleration as before.
b)Yes, keys will accelerate towards the floor faster if it is a constant speed than it is moving downward because if the elevator is accelerating downward, the downward change in velocity of the keys is at least partially matched by a downward change in the velocity of the of the elevator.
#1
Volume of lead = 100 cm^3
density of lead = 11.34 g/cm^3
mass of the lead piece = density * volume


so its weight in air will be given as

now the buoyant force on the lead is given by


now as we know that


so by solving it we got
V = 11.22 cm^3
(ii) this volume of water will weigh same as the buoyant force so it is 0.11 N
(iii) Buoyant force = 0.11 N
(iv)since the density of lead block is more than density of water so it will sink inside the water
#2
buoyant force on the lead block is balancing the weight of it




(ii) So this volume of mercury will weigh same as buoyant force and since block is floating here inside mercury so it is same as its weight = 11.11 N
(iii) Buoyant force = 11.11 N
(iv) since the density of lead is less than the density of mercury so it will float inside mercury
#3
Yes, if object density is less than the density of liquid then it will float otherwise it will sink inside the liquid
Answer:
the inductive reactance of the coil is 1335.35 Ω
Explanation:
Given;
inductance of the coil, L = 250 mH = 0.25 H
effective current through the coil, I = 5 mA
frequency of the coil, f = 850 Hz
The inductive reactance of the coil is calculated as;

Therefore, the inductive reactance of the coil is 1335.35 Ω