All categories

3 years ago

A ball is dropped from the top of a 77 m building. With what speed does the ball hit the ground? _________ m/s

Physics

1 answer:

vitfil [10]3 years ago

3 0

Answer:

38.87 m/s

Explanation:

Given that the ball is dropped from a height = 77 m

u = 0 m/s

s = 77 m

a = g = 9.81 m/s²

Applying the expression as:

$v^2-u^2=2as$

Applying values as:

$v^2-u^2=2as\\\Rightarrow v=\sqrt{2as+u^2}\\\Rightarrow v=\sqrt{2\times 9.81\times 77+0^2}\\\Rightarrow v=38.87\ m/s$

<u>The speed with which the ball hit the ground = 38.87 m/s</u>

You might be interested in

What is the electrical consumption in KVA of a motor powered by a 3-phase, 60 Hz, 460 VAC supply that continuously draws 17 A

MrRa [10]

Answer:

15.34 kVA

Explanation:

A motor is a device that converts electrical energy into mechanical energy. It takes in electrical energy at the input and produce torque (motion) at the output.

The power consumption for a three phase motor is the product of voltage and current and √3. The √3 is because it is a three phase supply.

Hence Power (P) =√3 × voltage (V) × current (I)

P = √3 × V × I

Given that voltage (V) = 460 V, current (I) = 17 A. Hence:

P = √3 × V × I = √3 × 460 × 17 = 13544.64 VA

But 1000 VA = 1 kVA. Hence:

$P=13544.64\ VA*\frac{1\ kVA}{1000\ VA}=13.54\ kVA$

8 0

3 years ago

Plz do all plz i will give brainest and thanks to best answer do it right

lara31 [8.8K]

Answer:

I'm not really sure but I think it's choice a

5 0

3 years ago

Read 2 more answers

You were driving your car to UTD at a speed of 35 miles per hour. You stopped at the FloydCampbell intersection with the signal

ser-zykov [4K]

Answer:

green light have high energy

Explanation:

We have given the wavelength of the red light $\lambda =6.45\times 10^{-5}cm=6.45\times 10^{-7}m$

Speed of the light $c=3\times 106{8}m/sec$

The energy of the signal is given by $E=h\nu =h\frac{c}{\lambda }=\frac{6.67\times 10^{-34}\times 3\times 10^{8}}{6.45\times 10^{-7}}=3.1023\times 10^{-15}j$

The frequency of the green light is given by:

$f=5.80\times 10^{14}s^{-1}$

So energy $E=h\nu =6.67\times 10^{-34}\times 5.80\times 10^{14}=3.8686\times 10^{-19}j$

So green light have high energy

8 0

3 years ago

A student is provided with a battery-powered toy car that the manufacturer claims will always operate at a constant speed. The s

guapka [62]

Answer:

a. Photogates placed at the beginning, end, and at various locations along the track that the car travels on.

b. A meterstick to measure the distance of the track that the car travels on.

Explanation:

Physics can be defined as the field or branch of science that typically deals with nature and properties of matter, motion and energy with respect to space, force and time.

In this scenario, a student is provided with a battery-powered toy car that the manufacturer claims will always operate at a constant speed. The student must design an experiment in order to test the validity of the claim.

Therefore, to test the validity of the claim, the student should use the following measuring tools;

a. Photogates placed at the beginning, end, and at various locations along the track that the car travels on. This device is typically used to measure time with respect to the rate of change of the interruption or block of an infra-red beam.

b. A meterstick to measure the distance of the track that the car travels on.

Hence, with these two devices the student can effectively measure or determine the validity of the claim.

5 0

3 years ago

ASK YOUR TEACHER A meter stick is found to balance at the 49.7-cm mark when placed on a fulcrum. When a 51.5-gram mass is attach

Simora [160]

Answer:

0.114 kg or 114 g

Explanation:

From the diagram attaches,

Taking the moment about the fulcrum,

sum of clockwise moment = sum of anticlockwise moment.

Wd = W'd'

Where W = weight of the mass, W' = weight of the meter rule, d = distance of the mass from the fulcrum, d' = distance of the meter rule.

make W' the subject of the equation

W' = Wd/d'................ Equation 1

Given: W = mg = 0.0515(9.8) = 0.5047 N, d = (39.2-16) = 23.2 cm, d' = (49.7-39.2) = 10.5 cm

Substitute these values into equation 1

W' = 0.5047(23.2)/10.5

W' = 1.115 N.

But,

m' = W'/g

m' = 1.115/9.8

m' = 0.114 kg

m' = 114 g

6 0

3 years ago