30. Light has been described as a ___ and a __

A ball is dropped from an upper floor, some unknown distance above your apartment. As you look out of your window, which is 1.50

laila [671]

Answer:

The ball is dropped at a height of 9.71 m above the top of the window.

Explanation:

<u>Given:</u>

Height of the window=1.5 m
Time taken by ball to cover the window height=0.15

Now using equation of motion in one dimension we have

$s=ut+\dfrac{at^2}{2}$

Let u be the velocity of the ball when it reaches the top of the window

then

$1.5=0.15u+\dfrac{9.8\times0.15^2}{2}\\u=3.96\ \rm m/s\\$

Now u is the final velocity of the ball with respect to the top of the building

so let t be the time taken for it to reach the top of the window with this velocity

$3.96=gt\\t=0.4\ \rm s\\$

Let h be the height above the top of the window

$h=\dfrac{gt^2}{2}\\\\h=\dfrac{9.8\times 0.4^2}{2}\\h=9.71\ \rm m$

3 0

3 years ago

A child, hunting for his favorite wooden horse, is running on the ground around the edge of a stationary merry-go-round. The ang

olga55 [171]

Answer:

9.22 s

Explanation:

One-quarter of a turn away is 1/4 of 2π, or π/2 which is approximately 1.57 rad

Let t (seconds) be the time it takes for the child to catch up with the horse. We would have the following equation of motion for the child and the horse:

For the child: $s_c = \omega_ct = 0.233t$

For the horse: $s_h = s_0 + a_ht^2/2 = 1.57 + 0.0136t^2/2 = 1.57 + 0.0068t^2$

For the child to catch up with the horse, they must cover the same angular distance within the same time t:

$s_c = s_h$

$0.233t = 1.57 + 0.0068t^2$

$0.0068t^2 - 0.233t + 1.57 = 0$

$t= \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}$

$t= \frac{0.233\pm \sqrt{(-0.233)^2 - 4*(0.0068)*(1.57)}}{2*(0.0068)}$

$t= \frac{0.233\pm0.11}{0.0136}$

t = 25.05 or t = 9.22

Since we are looking for the shortest time we will pick t = 9.22 s

6 0

3 years ago

A hammer is used to hit a nail into a board. Which statement is correct about the forces at play between the nail and the hammer

emmasim [6.3K]

Answer:

Hewo My Lovelys!!

Answer is down below!!

Explanation:

The answer is C) The nail exerts an equal force on the hammer in the opposite direction.

Reason: The Newtons third law states that there is an equal an opposite reaction for every action. When hammer pushes the nail, the nail will push the hammer back in opposite direction. When the hammer hits a nail then nail will exert the equal and opposite force to the hammer. These both objects will exert force on each other in opposite directions.

Hope this helps!! =3

Have a great day, evening, of night!! <3

~ XxGhostMosskitxX

5 0

3 years ago

Read 2 more answers

When water freezes, its volume increases by 9.05%. What force per unit area is water capable of exerting on a container when it

AnnZ [28]

Answer:

The Pressure is 0.20 MPa.

(b) is correct option.

Explanation: