Ask question

Ask question

All categories

12 days ago

8

An object is released from rest near and above Earth’s surface from a distance of 10m. After applying the appropriate kinematic

equation, a student predicts that it will take 1.43s for the object to reach the ground with a speed of 14.3m/s . After performing the experiment, it is found that the object reaches the ground after a time of 3.2s. How should the student determine the actual speed of the object when it reaches the ground? Assume that the acceleration of the object is constant as it falls.

1 answer:

serg [1.1K]12 days ago

4 0

Answer:

v_y = 12.54 m/s

Explanation:

Given values:

- Initial vertical height y_o = 10 m

- Initial velocity v_y,o = 0 m/s

- The object's acceleration in the air = a_y

- The actual time taken to reach the ground t = 3.2 s

Find:

- How to calculate the object's speed when it arrives at the ground?

Solution:

- Apply kinematic equations to find the actual acceleration of the ball when it reaches the ground:

y = y_o + v_y,o*t + 0.5*a_y*t^2

0 = 10 + 0 + 0.5*a_y*(3.2)^2

a_y = - 20 / (3.2)^2 = 1.953125 m/s^2

- Use the total energy conservation principle of the system:

E_p - W_f = E_k

Where, E_p = m*g*y_o

W_f = m*a_y*(y_i - y_f)..... Reflecting air resistance

E_k = 0.5*m*v_y^2

Thus, m*g*y_o - m*a_y*(y_i - y_f) = 0.5*m*v_y^2

g*(10) - (1.953125)*(10) = 0.5*v_y^2

v_y = sqrt(157.1375)

v_y = 12.54 m/s

You might be interested in

Two loudspeakers 42.0 m apart and facing each other emit identical 115 Hz sinusoidal sound waves in a room where the sound speed

ValentinkaMS [1144]

Answer:

She will be located in a loud area.

Explanation:

To evaluate whether Susan is situated in a quiet or loud area, we must first ascertain the difference in the sound waves reaching her from the two speakers.

If we refer to d₁ as the distance to speaker A, which measures 19.5 m, then d₂ to the other speaker is calculated as follows:

d₂ = 42.0 m - 19.5 m = 22.5 m

This reveals that the path difference between both speakers is:

d = d₂-d₁ = 22.5 m -19.5 m = 3.0 m

Next, we relate this distance to the sound wave's wavelength; for constructive interference, the path difference must equal an even multiple of half the wavelength:

d = (2n)*(λ/2)

To determine λ, we know that for any wave, the relationship between speed, frequency, and wavelength holds:

v = λ*f

<pwhere v="345" m="" and="" f="115" we="" can="" calculate="">

λ = v/f = 345 m/s / 115 (1/s) = 3.0 m.

Since the difference between the distances to Susan from both speakers corresponds exactly to one wavelength, this indicates that both waves arrive at the same phase, resulting in constructive interference, thus labeling it as a loud area.

</pwhere>

5 0

3 days ago

A household refrigerator runs one-fourth of the time and removes heat from the food compartment at an average rate of 800 kJ/h.

Ostrovityanka [942]

Answer:

1454.54 kJ/h or 0.404 kW

Explanation:

Provided:

The heat being removed by the refrigerator is 800 kJ/h.

The refrigerator's coefficient of performance (COP) is 2.2.

Since the refrigerator operates for one-fourth of the time,

it effectively removes heat, Q = $4\times 800 kJ/h$ = 3200 kJ/h.

Next, the power consumed by the refrigerator during its operation is calculated as:

$\frac{Q}{COP}$

= $\frac{3200 kJ/h}{2.2}$ .

= 1454.54 kJ/h

Thus, the fridge uses 1454.54 kJ/h

or 0.404 kW (given 1 kW = 3600 kJ/h).

4 0

2 days ago

help please!! A runner at a speed of 3.5 m/s comes to a stop in 0.15 seconds. What is the deceleration?

Maru [1053]

Answer:

The runner's deceleration is -23.33 $\frac{m}{s^{2} }$

Given:

Initial speed = 3.5 $\frac{m}{s}$

Final speed = 0 $\frac{m}{s}$

Time taken = 0.15 s

To determine:

Deceleration of the runner =?

Used Formula:

Using the first equation of motion,

v = u + at

Where, v = final speed

u = initial speed

a = deceleration

t = duration

Solution:

<pusing the="" first="" equation="" of="" motion="">

v = u + at

Where, v = final speed

u = initial speed

a = deceleration

t = duration

0 = 3.5 + a (0.15)

-3.5 = 0.15 (a)

a = $\frac{-3.5}{0.15}$

a = -23.33 $\frac{m}{s^{2} }$

The negative sign indicates that this represents deceleration.

Hence, the deceleration of the runner is -23.33 $\frac{m}{s^{2} }$

</pusing>

7 0

1 day ago

If you are anchored in a fixed spot, and a set of six waves pass underneath you during a 60 second time interval, what is the wa

Ostrovityanka [942]

Answer:

Explanation:

Within a duration of 60 seconds, six waves are observed.

With a total of 6 waves,

this equates to 3 wavelengths.

As a result,

the period for each wavelength is calculated as 60 divided by 3.

Thus, period = 20 seconds.

According to the frequency-period relationship,

f = 1 / T

f = 1 / 20

f = 0.05 Hz

5 0

2 days ago

Simone is walking her dog on a leash. The dog is pulling with a force of 32 N to the right and Simone is pulling backward with a

ValentinkaMS [1144]

Conclusion:

The total net force acting on the objects is 16 N, directed towards the right.

Clarification:

It is stated that,

The force exerted by the dog, $F_1 = 32\ N$ (to the right)

The force exerted by Simone, $F_2 = -16\ N$ (backward)

Here, assume the backward direction is negative and the right direction is positive.

The net force will move in the direction where the larger force is present. The net force can be calculated as:

$F=F_1+F_2$

$F=32+(-16)$

F = 16 N

Thus, the net force amounts to 16 N, acting towards the right.

6 0

3 days ago

Read 2 more answers