Answer:
The height of the building is 88.63 m.
Explanation:
Given;
initial component of vertical velocity,
= 12 m/s sin 26° = 5.26 m/s
initial horizontal component of the velocity,
= 12 m/s cos 26° =10.786 m/s
horizontal distance traveled by the rock, x = 40.4 m
time of flight is calculated as;
x =
t
t = x / 
t = 40.4 / 10.786
t = 3.75 s
Determine the final vertical velocity of the ball;

Determine the height of the rock;

Therefore, the height of the building is 88.63 m.
Answer:
The forces acting on the pen which is still on the table can have two forces acting on them. The forces are gravitational force and the equal and opposite force to the gravitational forces.
The equal and opposite forces that is applied on the pen keeps the pen still on the table.
So, the statement that no force is applied on the pen which is kept still on the table is wrong as two forces are applied on the pen.
As both the forces are equal and opposite so it is cancelled and is still.
The possible units for impulse would be:
<span>(N. s)
</span><span>(kg. m/s)</span>
Answer:
v = 18.84 m/s
Explanation:
Given that,
The length of the string, r = 1.5 m (it will act as radius)
The rubber stopper makes 120 complete circles every minute.
Since, 1 minute = 60 seconds
It means, its frequency is 2 circles every second.
Let we need to find the average speed of the rubber stopper. It can be calculated as follows :

d is distance,
and 1/T = f (frequency)

So, the average speed of the rubber stopper is 18.84 m/s.