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
stiv31 [10]
3 years ago
6

A child is sitting on the seat of a swing with ropes 5 m long. Her father pulls the swing back until the ropes make a 30o angle

with the vertical and then releases the swing. If air resistance is neglected, what is the speed of the child at the bottom of the arc of the swing when the ropes are vertical?
Physics
1 answer:
morpeh [17]3 years ago
7 0

Answer:

v = 3.7 m/s

Explanation:

As the swing starts from rest, if we choose the lowest point of the trajectory to be the zero reference level for gravitational potential energy, and if we neglect air resistance, we can apply energy conservation as follows:

m. g. h = 1/2 m v²

The only unknown (let alone the speed) in the equation , is the height from which the swing is released.

At this point, the ropes make a 30⁰ angle with the vertical, so we can obtain the vertical length at this point as L cos 30⁰, appying simply cos definition.

As the height we are looking for is the difference respect from the vertical length L, we can simply write as follows:

h = L - Lcos 30⁰ = 5m -5m. 0.866 = 4.3 m

Replacing in the energy conservation equation, and solving for v, we get:

v = √2.g.(L-Lcos30⁰) = √2.9.8 m/s². 4.3 m =3.7 m/s

You might be interested in
A quantity of hot water at 91°C and another cold one at 12°C.
Burka [1]

Answer:

m_{cold}=567kg\\\\m_{hot}=233kg

Explanation:

Hello!

In this case, since equilibrium temperature problems involve the mass, specific heat and temperature change for the substances at different temperatures, we can write:

m_{cold}C_{cold}(T_{eq}-T_{cold})=-m_{hot}C_{hot}(T_{eq}-T_{hot})

Thus, since we are talking about water and they both have the same specific heat, we can write:

m_{cold}(T_{eq}-T_{cold})=-m_{hot}(T_{eq}-T_{hot})

Now, we plug in the temperatures to obtain:

m_{cold}(35-12)+m_{hot}(35-91)=0\\\\23m_{cold}-56m_{hot}=0

Next, since the total volume of water is 800 L, since it has a density of 1kg/L, we infer the total mass is 800 kg; that is why we can write a 2x2 system of simultaneous equations:

\left \{ {{23m_{cold}-56m_{hot}=0} \atop {m_{cold}+m_{hot}=800}} \right.

Thus, the masses of both cold and hot water turn out:

m_{cold}=567kg\\\\m_{hot}=233kg

Best regards!

7 0
3 years ago
A race car travels 40 m/s around a banked (45° with the horizontal) circular (radius = 0.20 km) track. What is the magnitude of
OLEGan [10]

Answer:

c)F_{net} = 0.640 kN

Explanation:

As we know that resultant force is the net force that is acting on the system

As per Newton's II law we know that net force is product of mass and acceleration

so we will have

F_{net} = ma

here we know

m = 80 kg

for circular motion acceleration is given as

a_c = \frac{v^2}{R}

a_c = \frac{40^2}{200} = 8 m/s^2

now we have

F_{net} = 80 \times 8

F_{net} = 640 N

F_{net} = 0.640 kN

7 0
3 years ago
An airplane has an average speed of 740 mph
crimeas [40]

Answer:

2590

Explanation:

7 0
3 years ago
Find the acceleration a body whose velocity increases from 11m/s to 33m/s in 10 seconds
solong [7]

Answer:

1.1 m/(s)^2

Explanation:

u=11 m/s

v=33 m/s

t=10s

v=u+at

=> 33=22+(a)(10)

=> 33-22=10a

=> 10a=11

=> a=11/10=1.1 m/(s)^2

7 0
2 years ago
What if m1 is initially moving at 3.4 m/s while m2 is initially at rest? (a) find the maximum spring compression in this case?
Lisa [10]
<span>Ans : Initial E = KE = ½mv² = ½ * 1.2kg * (2.2m/s)² = 2.9 J max spring compression where both velocities are the same: conserve momentum: 1.2kg * 2.2m/s = (1.2 + 3.2)kg * v → v = 0.6 m/s which means the combined KE = ½ * (1.2 + 3.2)kg * (0.6m/s)² = 0.79 J The remaining energy went into the spring: U = (2.9 - 0.79) J = 2.1 J = ½kx² = ½ * 554N/m * x² x = 0.0076 m ↠(a)</span>
7 0
3 years ago
Other questions:
  • How is mass and inertia related
    9·1 answer
  • A concave lens is used to form an image. The diagram shows three incident rays that pass the object and then reach the lens. How
    13·2 answers
  • Which step follows the identification of the problem in the technological design process?
    12·1 answer
  • Light enters from air into diamond which has refractive index of 2.42 calculate the speed of light in diamond the speed of light
    13·1 answer
  • A 10 kg weight is suspended in the air by a strong cable. How much work is done, per unit time, in suspending the weight
    14·1 answer
  • HELPPPPP ASAP WILL GIVE brainly to correct answer
    6·2 answers
  • If a wave has a wavelength of 2m and a frequency of 500 hz, what is its speed
    13·1 answer
  • While a roofer is working on a roof that slants at 36.0 ° above the horizontal, he accidentally nudges his 86 0 N toolbox, caus
    6·1 answer
  • Explain the difference between potential energy, kinetic energy, and mechanical energy?
    11·1 answer
  • Explain why the moon orbits the earth while the earth orbits the sun
    9·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!