Does net force stay the same when a massless pulley is replaced by a pulley with mass

From because when held inhands stmah 3.in an experiment to determine the density of Sand using a density bottle, the following m

BARSIC [14]

What argument does Minow make in his speech?

A. Parents should demand better programs for their children to watch in the evenings.

B. People watch too much television, which leads to boredom and violence.

C. Television executives have a responsibility to provide better programming.

D. The nation's children depend on television to entertain and educate them.

4 0

3 years ago

A boy of mass 80 kg slides down a vertical pole, and a frictional force of 480 N acts on him. What is his acceleration as he sli

olga_2 [115]

Answer:

His acceleration is $\overrightarrow{a}=4\frac{m}{s^{2}}$

Explanation:

Newton's second law states that acceleration of a body is cause by a net force, the relation between them is:

$\sum\overrightarrow{F}=m\overrightarrow{a}$

On the boy there're acting two forces, his weight (W) that points downward and the frictional force (f) that points upward (they boy moves downward and friction always is opposite to movement). So $\sum\overrightarrow{F}=\overrightarrow{W}+\overrightarrow{f}$ so (1) is:

$\overrightarrow{W}+\overrightarrow{f}=m\overrightarrow{a}$

Using the positive direction downward weight and gravitational acceleration(g) are positive and friction force is negative:

$W-f=m\overrightarrow{a}$ , solving for a:

$\overrightarrow{a}=\frac{W-f}{m}$ , weight is mg:

$\overrightarrow{a}=\frac{mg-f}{m}=\overrightarrow{f}=\frac{(80kg)(10\frac{m}{s^{2}})-(480)}{80}$

$\overrightarrow{a}=4\frac{m}{s^{2}}$

6 0

4 years ago

When the mover pushes the box, two equal forces result. Explain why the box moves

pychu [463]

The mover is pushing on the box, meaning that when hes pushing on the box hes adding force to the box to make it move. The box cant move without force.

7 0

3 years ago

A sound wave has a frequency of 741 hz in air a wavelength of 0.47m what is the temperature of the air as soon as the below city

nekit [7.7K]

Answer:

Temperature when sound wave with wavelength 0.47m has frequency 741 hz is 188 degrees Centigrade.

Step-by-Step Explanation:

Given:

Speed of sound at 0 degrees centigrade = 235 ms

frequency = f = 741 hz

wavelength = w = 0.47m

speed of sound wave = wavelength * frequency = 741 * 0.47 = 348.27 m/s

Using the formula for speed of sound at a specific temperature:

Speed of sound at T degrees Centigrade = Speed of sound at 0 degrees + 0.6 * T

When speed of sound is 348 m/s, the temperature is given by:

348 = 235 + 0.6(T)

T = (348-235)/0.6

T = 188 degrees Centigrade

6 0

3 years ago

The mean time between collisions for electrons in room temperature copper is 2.5 x 10-14 s. What is the electron current in a 2

Darya [45]

Answer:

1.87 A

Explanation:

τ = mean time between collisions for electrons = 2.5 x 10⁻¹⁴ s

d = diameter of copper wire = 2 mm = 2 x 10⁻³ m

Area of cross-section of copper wire is given as

A = (0.25) πd²

A = (0.25) (3.14) (2 x 10⁻³)²

A = 3.14 x 10⁻⁶ m²

E = magnitude of electric field = 0.01 V/m

e = magnitude of charge on electron = 1.6 x 10⁻¹⁹ C

m = mass of electron = 9.1 x 10⁻³¹ kg

n = number density of free electrons in copper = 8.47 x 10²² cm⁻³ = 8.47 x 10²⁸ m⁻³

$i$ = magnitude of current

magnitude of current is given as

$i = \frac{Ane^{2}\tau E}{m}$

$i = \frac{(3.14\times 10^{-6})(8.47\times 10^{28})(1.6\times 10^{-19})^{2}(2.5\times 10^{-14}) (0.01)}{(9.1\times 10^{-31})}$

$i$ = 1.87 A

4 0

3 years ago