Answer:

Explanation:
From the question we are told that:
Height of window 
Height of window off the ground 
Time to fall and drop
Generally the Newton's equation motion is mathematically given by

Where



Generally the Newton's equation motion is mathematically given by

Where





Therefore the ball’s initial speed

Answer:
1.98s
Explanation:
The time taken to hit the ground is given by
h=ut+ 1/2 at^2
but u =0
so we have
h=1/2at^2
making t the subject
t=√2h/g
√2×19.6/10
1.98s
Answer:
B) the change in momentum
Explanation:
Impulse is defined as the product between the force exerted on an object (F) and the contact time (
)

Using Newton's second law (F = ma), we can rewrite the force as product of mass (m) and acceleration (a):

However, the acceleration is the ratio between the change in velocity (
) and the contact time (
):
, so the previous equation becomes

And by simplifying
,

which corresponds to the change in momentum of the object.
Answer:
The concentration of OH⁻ in the mixture is 0.05 M
Explanation:
The reaction of neutralization between HCl and NaOH is the following:
H⁺(aq) + OH⁻(aq) ⇄ H₂O(l)
The number of moles of HCl is:

Similarly, the number of moles of NaOH is:

Now, from the reaction of HCl and NaOH we have the following number of moles of NaOH remaining:

Finally, the concentration of OH⁻ in the mixture is:
Therefore, the concentration of OH⁻ in the mixture is 0.05 M.
I hope it helps you!
In physics, work is defined as the total energy when an object is moved to a certain displacement by the application of external force. It is calculated by the expression W = Fd. For this case, the displacement is apparently zero, then there is no work in the system above.