Answer:
Option B. 2.8 s
Explanation:
The following data were obtained from the question:
Initial velocity (u) = 27 m/s
Angle of projection (θ) = 30
Acceleration due to gravity (g) = 9.8 m/s²
Time of flight (T) =?
The time of flight of the ball can be obtained as follow:
T = 2uSineθ / g
T = 2 × 27 × Sine 30 / 9.8
T = 2 × 27 × 0.5 / 9.8
T = 27 / 9.8
T = 2.8 s
Therefore, time of flight of the ball is 2.8 s
Answer:
Answer D : about 1067 meters
Explanation:
There are two steps to this problem:
1) First find the time it takes the plane to stop using the equation for the acceleration:

Where Vf is the final velocity of the plane (in our case: zero )
Vi is the initial velocity of the plane (in our case: 80 m/s)
is the acceleration (in our case -3 m/s^2 - notice negative value because the velocity is decreasing)

with units corresponding to seconds given the quantities involved in the calculation.
2) Second knowing the time it took the plane to stop, now use that time in the equation for the distance traveled under accelerated motion:

Where the answer results in units of meters given the quantities used in the calculation.
We round this to 1067 meters
Answer:
The initial velocity is 50 m/s.
(C) is correct option.
Explanation:
Given that,
Time = 10 sec
For first half,
We need to calculate the height
Using equation of motion

....(I)
For second half,
We need to calculate the time
Using equation of motion



Put the value of h from equation (I)


According to question,


Put the value of t₁ and t₂



Here, g = 10
The initial velocity is


Hence, The initial velocity is 50 m/s.