All categories

2 years ago

PLEASE HELP!!!

Physics

1 answer:

lilavasa [31]2 years ago

7 0

Answer:

ω = 3.1 rad/s

θ = 36° from vertical

Explanation:

I will ASSUME that the bob and string is acting as a pendulum.

Please understand that the string will break when the bob is at the lowest point of the swing where the vectors of gravity and centripetal acceleration align. It will NOT break at the angle of maximum inclination measured from vertical. This angle is only a component of the maximum potential energy that gets converted to maximum kinetic energy at the lowest point of the swing.

At the bottom of the swing, the string must support the weight of the bob plus supply the required centripetal acceleration.

F = mg + mω²R

F/m = g + ω²R

F/m - g = ω²R

ω = √((F/m - g)/R)

ω = √((3/0.220 - 9.8)/0.40)

ω = 3.09691...

ω = 3.1 rad/s

Potential energy will convert to kinetic energy

mgh = ½mv²

h = v²/2g

R - Rcosθ = v²/2g

R(1 - cosθ) = v²/2g

1 - cosθ = v²/2gR

cosθ = 1 - v²/2gR

cosθ = 1 - (Rω)²/2gR

cosθ = 1 - Rω²/2g

cosθ = 1 - 0.40(3.1²)/(2(9.8))

cosθ = 0.804267

θ = 36.46045...

θ = 36°

You might be interested in

A model engine accelerated forward from rest along a straight track at 10.0 m/s2 for 3.0 seconds. It then accelerates coward at

Mrac [35]

Answer:

17.2 seconds

Explanation:

Given:

v₀ = 0 m/s

a₁ = 10.0 m/s²

t₁ = 3.0 s

a₂ = 16 m/s²

t₂ = 5.0 s

a₃ = -12 m/s²

v₃ = 0 m/s

Find: t

First, find v₁:

v₁ = a₁t₁ + v₀

v₁ = (10.0 m/s²) (3.0 s) + (0 m/s)

v₁ = 30 m/s

Next, find v₂:

v₂ = a₂t₂ + v₁

v₂ = (16 m/s²) (5.0 s) + (30 m/s)

v₂ = 110 m/s

Finally, find t₃:

v₃ = a₃t₃ + v₂

(0 m/s) = (-12 m/s²) t₃ + (110 m/s)

t₃ = 9.2 s

The total time is:

t = t₁ + t₂ + t₃

t = 3.0 s + 5.0 s + 9.2 s

t = 17.2 s

Round as needed.

4 0

3 years ago

A wire loop is placed inside a magnetic field. the magnetic flux is maximized when the angel between the field lines and the sur

klasskru [66]

When magnetic field lines and surface area are perpendicular to each other.

6 0

3 years ago

Carbon dioxide in a piston-‐‐cylinder is expanded in a polytropic manner. The initialtemperature and pressure are 400 K and 550

Arisa [49]

Answer:

q_poly = 14.55 KJ/kg

Explanation:

Given:

Initial State:

P_i = 550 KPa

T_i = 400 K

Final State:

T_f = 350 K

Constants:

R = 0.189 KJ/kgK

k = 1.289 = c_p / c_v

n = 1.2 (poly-tropic index)

Find:

Determine the heat transfer per kg in the process.

Solution:

-The heat transfer per kg of poly-tropic process is given by the expression:

q_poly = w_poly*(k - n)/(k-1)

- Evaluate w_poly:

w_poly = R*(T_f - T_i)/(1-n)

w_poly = 0.189*(350 - 400)/(1-1.2)

w_poly = 47.25 KJ/kg

-Hence,

q_poly = 47.25*(1.289 - 1.2)/(1.289-1)

q_poly = 14.55 KJ/kg

4 0

3 years ago

Describe a scenario where a car's speed could stay the same, but the acceleration changes.

k0ka [10]

Answer:

An object's acceleration is the rate its velocity (speed and direction) changes. Therefore, an object can accelerate even if its speed is constant - if its direction changes.

Explanation:

8 0

3 years ago

A low C (f = 65Hz) is sounded on a piano. If the length of the piano wire is 2.0 m and its mass density is 5.0 g/m2, determine t

Pie

Answer:

338N

Explanation:

Use the formula $f=\frac{\sqrt{\frac{T}{\frac{M}{L}} } }{2L}$

f is the frequency, T the string tension, M the mass, and L the length

convert units to seconds, kilograms, meters

$65Hz\ =\ \frac{\sqrt{\frac{T}{\frac{0.005kg}{m}}}}{2\cdot2m}$

now solve for T

sqrt(T/.005) = 65*4 = 260

T = 338N

8 0

3 years ago