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3 years ago

2. Which metal ion produces the light with the highest energy? Na+ Ca+ K+ Ba2+

1 answer:

5 0

"K+" is the one metal ion among the choices given in the question that produces <span>the light with the highest energy. The correct option among all the options that are given in the question is the third option or the penultimate option. I hope that the answer has actually come to your help.</span>

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A block of weight 45.7 N is hanging from a rope. The tension from the rope is pulling upward on the block. The block is accelera

viktelen [127]

<h2>Answer:</h2><h2></h2>

52.555 N

<h2>Explanation:</h2>

Let's use Newton's second law of motion here which states that the resultant force (∑F) acting on a body is the product of the mass (m) of the body and the acceleration (a) due to this force. i.e

∑F = m x a ---------------------(i)

<em>Now, let's get the resultant force;</em>

Two main forces are acting on the rope;

i. the weight (W) of the block acting downwards.

Where;

W = mass of block(m) x gravity(g) = m x g

ii. the tension (T) in the rope acting upwards.

Therefore, the resultant force is the vector sum of these two forces as follows;

∑F = - W + T [upward motion is taken as positive. hence -W and +T]

<em>Substitute ∑F = - W + T into equation (i) as follows;</em>

- W + T = m x a ---------------------(ii)

<em>From the question;</em>

* Weight (W) of the block = 45.7N

=> mass (m) of the block = W / g = 45.7 / 10 [Taking g = 10m/s²]

=> m = 4.57 kg

* acceleration (a) = 1.50m/s²

<em>Substitute these values into equation (ii) as follows;</em>

- 45.7 + T = 4.57 x 1.50

- 45.7 + T = 6.855

<em>Solve for T;</em>

T = 6.855 + 45.7

T = 52.555 N

Therefore, the tension in the rope is 52.555 N

6 0

4 years ago

A. What frequency is received by a person watching an oncoming ambulance moving at 115 km/h and emitting a steady 753 Hz sound f

nasty-shy [4]

Answer:

A)828.8Hz

B)869.2Hz

Explanation:

Here is a complete question;

What frequency is received by a person watching an oncoming ambulance moving at 115 km/h and emitting a steady 753 Hz sound from its siren? Speed of sound is 345m/s

b. What frequency does she receive after the ambulance has passed?

Vs= speed of the ambulance

, We convert to m/s for unit consistency

= 115 km/h= 115km× 1000m/1m × 1hr/3600s= 31.94m/s

Dopler effect is when observed frequency of wave changes with respect to the source or when observed moves relative to transmitting medium can be expressed as

f'=[ (v + vo)/(v- vs)]*f

=[ (v )/(v- vs)]*f

The sign vo and vs depends on vthe direction of the velocity

f= frequency of ambulance siren= 753Hz

v= speed of sound in air= 345m/s

Vo= speed of observer= 0

A) we are to determine the f' of ambulance as heard by person as ambulance approaching.

To find the frequency f' observed by the person we use the expresion below

Then substitute the values

f'=[ (v )/(v- vs)]*f

=[ (345)/(345-31.94)]×753

= 828.8Hz

B)What frequency does she receive after the ambulance has passed?

To find the frequency f' observed by the person we use the expresion below

Then substitute the values

f'=[ (v )/(v + vs)]*f

=[ (345)/(345 + 31.94)]×753

= 869.2Hz

4 0

3 years ago

Two blocks of masses 20 kg and 8.0 kg are connected togetherby

Dmitry [639]

Answer:

The tension is 14 N

Explanation:

For this problem we have to use newton's law, so:

$F=m*a$

The second string is connected to the mass of 8 kg, but the mass of 8 kg is connected to the mass of 20kg, so we can say that the second string is handling the two masses. so:

$F=28kg*0.5\frac{m}{s^2}=14N$

3 0

3 years ago

a bungee jumper momentarily comes to rest at the bottom of the dive before he springs back upward. at that moment, is the bungee

barxatty [35]

Answer:

Explanation:

No, the bungee jumper is not at equilibrium.

This can be explained when we consider a bungee jumper as a mass that is undergoing simple harmonic motion. At extreme points i.e. at the bottom, the velocity of the jumper is zero but not the acceleration because it is acting in the opposite direction that is why the jumper moves upward.

3 0

4 years ago

Read 2 more answers

Sprinting near the end of a race, a runner with a mass 63 kg accelerates from a speed of 25 m/s to a speed of 26 m/s in 54 s. To

gavmur [86]

Answer:

1.1655 N

Explanation:

Given that,

Initial speed, u = 25 m/s

Final speed, v = 26 m/s

Time taken, t = 54 s