Answer: 6.45 s
Explanation:
We have the following equation:
(1)
Where:
is the height when the rock hits the ground
the height at the edge of the cilff
the initial velocity
acceleration due gravity
time
(2)
Rearranging the equation:
(3)
At this point we have a quadratic equation of the form
, and we have to use the quadratic formula if we want to find
:
(4)
Where
,
, 
Substituting the known values and choosing the positive result of the equation:
(5)
This is the time it takes to the rock to hit the ground
Answer:
a) 16.46 seconds.
b) 13.46 seconds
c) 2.67 m/s²
Explanation:
Acceleration = a = 1.35 m/s²
Final velocity = v = 80 km/h = 
Initial velocity = u = 0
Equation of motion

Time taken to accelerate to top speed is 16.46 seconds.
Acceleration = a = -1.65 m/s²
Initial velocity = u = 80 km/h= 
Final velocity = v = 0

Time taken to stop the train from top speed is 13.46 seconds
Initial velocity = u = 80 km/h= 
Time taken = t = 8.3 s
Final velocity = v = 0

Emergency deceleration is 2.67 m/s²
Answer:
(Equation 10.3. 2): RS=R1+R2+R3+R4+R5=20Ω+20Ω+20Ω+20Ω+10Ω=90Ω
Answer:
The ratio of lengths of the two mathematical pendulums is 9:4.
Explanation:
It is given that,
The ratio of periods of two pendulums is 1.5
Let the lengths be L₁ and L₂.
The time period of a simple pendulum is given by :

or

Where
l is length of the pendulum

or
....(1)
ATQ,

Put in equation (1)

So, the ratio of lengths of the two mathematical pendulums is 9:4.
<span>Of the following gasses, CH4 will have the greatest rate of effusion at a given temperature.</span>