A stone of mass m = 1.05 kg is released from a height of h = 2.1 m into a pool of water. At a time of t = 1.83 s after hitting the surface of the water, the stone's velocity has decreased by 50%.
What is the magnitude of the average force the stone experiences, in newtons, during the time t?

Answer:

Explanation:

ignoring air resistance, the kinetic energy at water impact will equal the potential energy converted

½mv² = mgh

v = √(2gh)

v = √(2(9.81)2.1) = 6.4188... m/s

after impact, an impulse will result in a change of momentum.

There is a downward impulse due to gravity equal to the weight of the stone and an upward average force due to water resistance and buoyancy force.

FΔt = mΔv

(F - mg)Δt = m(vf - vi)

(F - mg) = m(vf - vi)/Δt

F = m(vf - vi)/Δt + mg

F = m((vf - vi)/Δt + g)

F = 1.05(((½(-6.4188) - -6.4188)/ 1.83) + 9.81)

F = 12.14198...

F = 12.1 N

The magnitude of the average force the stone experiences, will be 12.1 N.

Force is defined as the push or pulls applied to the body. Sometimes it is used to change the shape, size, and direction of the body. Force is defined as the product of mass and acceleration. Its unit is Newton.

The given data in the problem is;

m is the stone mass = 1.05 kg

The height is h, = 2.1 m i

The time is, t = 1.83 s

Velocity decreased by 50%.

From the law of conservation of energy the kinetic energy is equal to the potential energy;

[tex]\rm \frac{1}{2} mv^2 = mgh \\\\ v = \sqrt{2gh}\\\\ v = \sqrt{2 \times 9.81 \times 2.1 } \\\\ v= 64188 \ m/sec.[/tex]

From Newton's second law of motion, the impulsive force is equal to the change in momentum;

[tex]\rm F \triangle T = m \traingle v \\\\ (F - mg) = \frac{v_f-v_i}{\triangle t } \\\\ F = \frac{v_f-v_i}{\triangle t } + mg \\\\ F =m\frac{v_f-v_i}{\triangle t + g} \\\\ F= 12.14 98 \\\\ F=12.1 N[/tex]

Hence the magnitude of the average force the stone experiences, will be 12.1 N.

To learn more about the force refer to the link;

https://brainly.com/question/26115859

Someone please help with this question. From my knowledge the answer I believe to be correct is 4Em but I’m still not so sure. Please explain!
Answer choices:
1/2 Em
Em
2Em
4Em

Một chất điểm khối lượng m=200g chuyển
động chậm dần với vận tốc biến đổi theo qui luật
v=30 – 0,4t2 (SI). Lực hãm tác dụng vào chất điểm
lúc t = 5 giây là
A. 8 N B. 0,8 N C. 4 N D. 0,4 N

The maximum speed with which an 1000 kg car makes a 180-degree turn is 10 m/s. The radius of the circle through which the car is turning is 24 m. Determine the force of friction and the coefficient of friction acting upon
the car.

What happens to the gravitational force between two objects if the distance between them triples?

A. The force increases by a factor of 9

B. The force decreases by a factor of 9

C. The force decreases by a factor of 3

D. The force increases by a factor of 3

What is the weight of a 5kg object at the surface of the earth?

A. 49N
B. 49kg
C. 5.0kg
D. 25N

You are standing 30 m due east of a 50 kg person who is running at a speed of 20 m/s due west. What is the magnitude of that person's angular momentum about you (in units of )

A 2.40 kg ball is attached to an unknown spring and allowed to oscillate. The figure below shows a graph of the ball’s position �� as a function of time . What are the oscillation’s: a. period; b. frequency; c. angular frequency; d. amplitude; and e. What is the force constant of the spring?

Two Blocks are connected by a massless rope over a massless,
frictionless pulley, as shown in the figure. The mass of block 2
is m2 = 10.1 kg, and the coefficient of kinetic friction
between block 2 and the incline is Mk = 0.200. The angle 0 of
the incline is 27.5º. If block 2 is moving up the incline at
constant speed, what is the mass mi of block 1?

One indicator NOT related to domestic violence is
violent attitudes
good nutrition
violations of court orders
substance abuse

What are the characteristics of high energy wave?

A. Low frequencies and short wavelengths.

B. High frequencies and long wavelengths.

C. Low frequencies and long wavelengths.

D. High frequencies and short wavelengths

4. Protons and neutrons are held together to form this _________

f. Protons and neutrons
2. TRUE or FALSE: An object that is positively charged contains all protons and no electrons
3. TRUE or FALSE: An object that is negatively charged could contain only electrons with me
accompanying protons
4. TRUE or FALSE: An object that is electrically neutral contains only neutrons.

a rocket ship is moving through space at 1000 m/s. It accelerates in the same direction at 4m/s/s. What is its speed after 100 seconds

Determine the rTo understand the concept of nodes of a standing wave.
The nodes of a standing wave are points where the displacement of the wave is zero at all times. Nodes are important for matching boundary conditions, for example that the point at which a string is tied to a support has zero displacement at all times (i.e., the point of attachment does not move).
Consider a standing wave, where y represents the transverse displacement of a string that extends along the x direction. Here is a common mathematical form for such a wave:

y(x,t)=Acos(kx)sin(ωt),

where A is the maximum transverse displacement of the string (the amplitude of the wave), which is assumed to be nonzero, k is the wavenumber, ω is the angular frequency of the wave, and t is time.
Part A
Which one of the following statements about wave y(x,t) is correct?

adius of the 236U nucleus.

1. A roller coaster with a mass of 800 kg sits stationary at the top of a section of track, 75 m above

the ground as shown. When the brake is released, it starts to roll down the track


2. For each height represented in the diagram, calculate the gravitational potential energy using

Ep = mgh. Show ONE SAMPLE calculation in the calculations section below and fill in Table 1 for

each of the heights of the roller coaster. (6 marks)


3. Assuming there is no friction, determine the mechanical kinetic energy using Ek = Etotal - Ep.

Show ONE SAMPLE calculation in the calculations section below and fill in Table 1 for each of

the heights of the roller coaster. (6 marks)


4. For each height represented in the diagram, calculate the velocity using = �2

. Show ONE

SAMPLE calculation in the calculations section below and fill in Table 1 for each of the heights of

the roller coaster. (6 marks)


5. Use your answers to graph how gravitational potential energy, mechanical kinetic energy, and

velocity change as the roller coaster changes height. Use different colours for the three lines on

the graph. Graph paper is provided below. (3 marks)


6. Repeat steps 1 – 5 above for a roller coaster cart that has a mass of 300 kg and enter your

results in Table 2.

Calculations:

800 kg roller coaster cart:

Sample calculation for gravitational potential energy:

Sample calculation for Mechanical kinetic energy:

Sample calculation for velocity:


300 kg roller coaster cart:

Sample calculation for gravitational potential energy:

Sample calculation for mechanical kinetic energy:

Sample calculation for velocity:


Results:

Table 1: Potential energy, kinetic energy, total energy, and velocity of the 800 kg roller coaster cart


Table 2: Potential energy, kinetic energy, total energy, velocity of the 300 kg roller coaster cart.


Graphs:

It’s graphing time. These graphs are a bit different than the ones you did in the

data analysis assignment at the beginning of the course. In this case you have

three things to graph on each graph. (One graph for the 800 kg roller coaster cart

and one graph for the 300 kg roller coaster cart.) You need to graph the

gravitational potential energy with respect to height, the mechanical kinetic

energy vs height, and the velocity vs height.

Let’s look at the energy graphs first. In this case both kinetic energy and

mechanical energy cover the same range of values. This means they can use the

same scale on the y-axis. So, you will use the left y-axis and the x-axis to graph

the kinetic energy vs height and the potential energy vs height. You will need a

legend to explain which line is which. Colour coding is a nice way to highlight this.

The velocity values are much different than the energy values. This means you

need a totally different scale. So, your left y-axis won’t work. You need to make a

second scale on the right y-axis for your velocity values. You will plot the points

the same way as normal, but you will use the numbers on the right-hand scale

instead. Again, be sure to add your velocity line to the legend with a separate

colour code.


Discussion Questions:

1. Describe the relationship between the gravitational potential energy and the mechanical kinetic

energy of the roller coaster on your graph. (2 marks)

2. Describe the shapes of each of the three lines in the graph. Explain why the velocity is different.

(4 marks)

3. Describe how mass affects the speed at the bottom of the roller coaster. (2 marks)

4. Describe how mass affects the gravitational potential energy and the mechanical kinetic energy

of the roller coaster. (2 marks)

5. At what point does the roller coaster have a maximum value for the following? Justify your

answer by explaining why. (2 marks each)

a. Gravitational potential energy

b. Mechanical energy

c. Velocity

6. In your calculations, you assumed that the roller coaster was frictionless. All real roller coasters

encounter friction. Describe how the actual values of the variables would differ, or not differ,

from your calculated values for a real roller coaster. (Hint: what form of energy would some of

the total energy be converted to if there was friction in the system?) (4 marks)

How you will be graded:

Grades will be based on answering questions to demonstrate an understanding of the material covered

in this unit. Point form answers are okay if ideas are complete and use vocabulary (Word Bank)

provided. For questions out of 4 marks, there are 4 responses expected.

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o
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