1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
kotegsom [21]
3 years ago
13

A rock is thrown horizontally from a bridge with a velocity of 17.0 m/s. It takes the rock 3.0 s to strike the water below. What

is the magnitude of the velocity of the rock just before it hits the water
Physics
1 answer:
zalisa [80]3 years ago
7 0

Answer:

V= 33.98 m/s

Explanation:

Given that

Horizontal speed ,u= 17 m/s

Time taken by rockets to strike the water ,t= 3 s

We know that acceleration due to gravity ,g= 9.81 m/s²

There is no any acceleration in the horizontal direction that is why the horizontal veloity will remain constant.

In the vertical direction

vy = uy+ g t

Initial velocity in vertical direction is 0 m/s.

vy= 0+ 9.81 x 3

vy = 29.43 m/s

The resultant velocity

V=\sqrt{v_y^2+u^2}

V=\sqrt{29.43^2+17^2}\ m/s

V= 33.98 m/s

You might be interested in
considere que o calor específico de um material presente nas cinzas seja c=0,8j/gc. Supondo que esse material entre na turbina a
drek231 [11]

Answer:

3120J

Explanation:

Given parameters:

C  = Specific heat capacity  = 0.8J/g°C

Initial temperature  = 20°C

Mass given   = 5g

Final temperature  = 800°C

Unknown:

Energy given to the mass  = ?

Solution:

To find the energy given to the mass, let us simply use the expression below:

          H   =   m   c   ΔT

H is the unknown, the energy supplied

m is the mass of the substance

c is the specific heat capacity

ΔT is the change in temperature

Input the variables;

            H    = 5  x   0.8    x    (800 - 20)  = 3120J

7 0
3 years ago
Desde una altura de 120 m se deja caer un cuerpo. Calcular a los 2,5 s i) la rapidez que lleva; ii) cuánto ha descendido; iii) c
stira [4]

Answer:

i) 24.5 m/s

ii) 30,656 m

iii) 89,344 m

Explanation:

Desde una altura de 120 m se deja caer un cuerpo. Calcule a 2.5 s i) la velocidad que toma; ii) cuánto ha disminuido; iii) cuánto queda por hacer

i) Los parámetros dados son;

Altura inicial, s = 120 m

El tiempo en caída libre = 2.5 s

De la ecuación de caída libre, tenemos;

v = u + gt

Dónde:

u = Velocidad inicial = 0 m / s

g = Aceleración debida a la gravedad = 9.81 m / s²

t = Tiempo de caída libre = 2.5 s

Por lo tanto;

v = 0 + 9.8 × 2.5 = 24.5 m / s

ii) El nivel que el cuerpo ha alcanzado en 2.5 segundos está dado por la relación

s = u · t + 1/2 · g · t²

= 0 × 2.5 + 1/2 × 9.81 × 2.5² = 30.656 m

iii) La altura restante = 120 - 30.656 = 89.344 m.

6 0
3 years ago
A 1500 kg car, initially traveling at 22.0 m/s, hits its brakes and skids to a stop. Determine the work done by friction.
Sedbober [7]

Answer:

<em>The work done by the car is 363 kJ</em>

Explanation:

Work : Work is said to be done when a Force moves an object through a certain distance. Work and Energy are interchangeable because they have the same unit. The unit of work is Joules (J).

Mathematically work done can be expressed as,

E = W = 1/2mv²

W =  1/2mv²................................ Equation 1

Where E = Energy, W = work done, m = mass of the car, v = velocity of the car

<em>Given: m=1500 kg, v=22 m/s</em>

<em>Substituting these values into equation 1</em>

<em>W = 1/2(1500)(22)²</em>

<em>W = 750 × 484</em>

<em>W = 363000 J</em>

<em>W = 363 kJ</em>

<em>Thus the work done by the car is 363 kJ</em>

8 0
3 years ago
Why do tin roofs make creaking sounds on hot days?
laiz [17]

Answer: Yes, on many slate-roofed homes as temperatures change, such as cooling at night or heating during the day, thermal expansion or contraction of the slates may cause movement that in turn causes snapping, popping, or cracking noises, even bangs and clanks or clicks from the roof.

Explanation:

8 0
3 years ago
Read 2 more answers
A toy car on a string is pulled across a table horizontally. The string is at an angle
ddd [48]
Which way is it being pulled?
6 0
3 years ago
Other questions:
  • By how much does the gravitational potential energy of a 54-kg pole vaulter change if her center of mass rises about 4.0 m durin
    9·2 answers
  • Electromagnetic waves do require a medium to travel.<br><br> True<br> False
    6·2 answers
  • The activation of the sympathetic division would prepare people for
    10·1 answer
  • A player kicks a ball across the grass. what causes the ball to slow down to stop
    14·1 answer
  • Look at the picture and help me plz
    7·2 answers
  • 6. A 1,780kg car moving at 14m/s takes a turn around a circle with a radius of 50.0m.
    5·1 answer
  • Make the following conversion: 34.9 cL = _____ hL
    8·1 answer
  • A picture that shows magnets that will repel
    6·1 answer
  • In an inelastic collision, as compared to an elastic collision, what is to be expected?.
    13·1 answer
  • Which of the following states that energy cannot be created or destroyed?
    9·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!