In which scenario is work being done on an object?

A forward horizontal force of 3 lb is used to pull a 60 lb sled at constant velocity on a frozen pond. the coefficent of (kineti

puteri [66]

It’s either 0.05 or 20. Assuming that the coefficient friction is a damping factor, I feel like 0.05 would be correct m

7 0

3 years ago

A fire engine approaches a wall at 5 m/s while the siren emits a tone of 500 Hz frequency. At the time, the speed of sound in ai

Svetach [21]

Answer:

The values is $f_b =14.9 \ beats/s$

Explanation:

From the question we are told that

The speed of the fire engine is $v = 5\ m/s$

The frequency of the tone is $f = 500 \ Hz$

The speed of sound in air is $v_s = 340 \ m/s$

The beat frequency is mathematically represented as

$f_b = f_a - f$

Where $f_a$ is the frequency of sound heard by the people in the fire engine and is is mathematically evaluated as

$f_a = [\frac{v_s + v }{v_s -v} ]* f$

substituting values

$f_a = [\frac{340 + 5 }{340 -5} ]* 500$

$f_a = 514.9 \ Hz$

Thus

$f_b =514.9 - 500$

$f_b =14.9 \ beats/s$

8 0

3 years ago

Neglecting friction, of a pendulum bob has 100 joules of kinetic energy at the bottom of its swing, how much potential energy do

galben [10]

100 joule of kinetic energy

7 0

3 years ago

A bowling ball of mass m = 1.7 kg drops from a height h = 14.2 m. A semi-circular tube of radius r = 6.2 m rest centered on a sc

marshall27 [118]

Answer:

W_net = mg + 2mgh/r

Explanation:

The forces applied in this motion of the bowling ball are both gravitational and centripetal forces.

Now, gravitational force is; F_g = mg

While centripetal force is; F_c = mv²/r

Since we want to express the net force in terms of the variables in the statement and we are not given "v", let's find an expression of v with the variables given.

Now, from Newton's equation of motion, at initial velocity of 0, v² = 2gh.

Thus;

F_c = 2mgh/r

Where;

m is ball mass

r is tube radius

h is fall height

Thus, the net force will be;

F_net = F_g + F_c

Now, Net force would be equal to the net weight that will be read on the scale.

Thus;

W_net = F_net = F_g + F_c

W_net = mg + 2mgh/r

8 0

3 years ago

if a cyclist is travelling a road due east at 12km/h and a wind is blowing from south-west at 5km/h. find the velocity of the wi

slamgirl [31]

Answer:

The velocity of wind with respect to cyclist is $-15.5 \widehat{i} - 3.5 \widehat{j}$ .

Explanation:

speed of cyclist = 12 km/h east

speed of wind = 5 km/h south west

Write the speeds in the vector form

$\overrightarrow{vc} = 12 \widehat{i}\\\\overrightarrow{vw} = - 5 (cos 45 \widehat{i} + sin 45 \widehat{j})\\\\\overrightarrow{vw} =-3.5 \widehat{i} - 3.5 \widehat{j}$

The velocity of wind with respect to cyclist is

$\overrightarrow{vw} =-3.5 \widehat{i} - 3.5 \widehat{j}\overrightarrow{v_(w/c)} = \overrightarrow{vw}-\overrightarrow{vc}\\\\\overrightarrow{v_(w/c)} = - 3.5 \widehat{i} - 3.5 \widehat{j} - 12 \widehat{i}\\\\\overrightarrow{v_(w/c)} =-15.5 \widehat{i} - 3.5 \widehat{j}$

7 0

3 years ago