# How do I find an unknown weight ?

• mushhhy
In summary, the problem involves a lab experiment with a car running on a frictionless rail and colliding with another stationary car. The weight of the car without batteries is 0.986kg and the impacted car is positioned at 100cm. The goal is to find the acceleration, mass, force, kinetic energy, work, weight of three Rayovac cells on the object, momentum with and without cells, and impulse upon collision. So far, the acceleration, mass, force, and kinetic energy have been calculated. The weight of the three Rayovac cells can be found using the formula Weight = Mass x Gravity, and the momentum and impulse upon collision can be calculated using their respective equations. The work is still in progress and
mushhhy
Here is the problem that was set up as a lab experiment.
We ran a car on a Rail (assumed to be frictionless) and collided it with another (stationary) car. There were three trials and I have gathered thwe average of the the
Next we added three rayovac cells to the car and repeated the same process.

I will provide the work already performed (i do not think it is correct) but here goes.

the weight of the car without batteries is 985.5g = 0.986kg

the impacted car car is posistioned at 100cm on the rail. Xi =100cm = 1m
average Xf = 38 cm = .37m

Ti =0, average Tf =4.25s

We are to find the following:

Here goes The problem states to find the following
1. Acceleration 5. Work
2. mass 6.the weight of three rayovac cells placed on the object
3. Force 7. momentum with and without cells
4. KE 8. Impulse upon collision

This is the work I have completed so far.
1.
a = (Vf - Vi/t), Vi = 0, Vf = d/t = -0.63m/4.25s = -0.15m/s
a = (-0.15m/s)/4.25s =-0.035m/s^2
2.
m = w/g = (0.986kg) / (9.8m/s^2) = 0.1N
3.
F = m x a = (0.1N) (-0.035m/s^2) = -3.5 x 10^-3 (N)(m/s^2)
4.
KE = (1/2)mv^2 = (1/2) (0.1N) (-0.15m/s)^2 = 11.25 x10^-4 J

5.
W = (FcosO)X = (3.5 x 10^-3) (-.62m) = -2.17 x10^-4 J

I do not know how to calculate the weight of the car with the cells.
The process is the same with 3 runs the average time and distance are

Xi = 100cm = 1m, Xf = 51.67cm, = .52m
Ti = 0 Tf = 3.25s

I have no idea how to do the rest of this exercise. I am willing to do the work but I need some direction . Any help at all will be greatly appreciated. I need to know how to do this work for a test in my next class meeting.

THANKS

!!!6. The weight of the three Rayovac cells placed on the object can be calculated using the formula:Weight = Mass x Gravity, where Mass is the mass of the object and gravity is 9.8 m/s2. So, the weight of the three Rayovac cells would be:Weight = 3 x 0.1 x 9.8 = 2.94 N.7. Momentum with Cells = Mass x Velocity = 0.1 x (-0.15) = -0.015 kg m/s.Momentum without Cells = Mass x Velocity = 0.986 x (-0.15) = -0.149 kg m/s.8. The impulse upon collision can be calculated using the equation: Impulse = Change in Momentum. The change in momentum in this case is the difference between the momentum with and without cells. Therefore, the impulse upon collision is:Impulse = -0.134 kg m/s.

To find the unknown weight, we need to use the formula F = ma, where F is the force, m is the mass, and a is the acceleration. In this experiment, we know the acceleration from the first part of the problem (a = -0.035m/s^2), and we can also calculate the force (F = -3.5 x 10^-3 (N)(m/s^2)).

Now, we can rearrange the formula to solve for the mass: m = F/a. Plugging in the values we know, we get: m = (-3.5 x 10^-3 (N)(m/s^2)) / (-0.035m/s^2) = 0.1kg. This is the mass of the car without batteries.

To find the weight, we need to multiply the mass by the acceleration due to gravity (g = 9.8m/s^2): w = mg = (0.1kg) (9.8m/s^2) = 0.98N. This is the weight of the car without batteries.

To find the weight of the car with the three Rayovac cells, we can follow the same process. The only difference is that the acceleration will be different, since the car now has more mass due to the added cells. We can calculate the new acceleration by taking the average of the three trials from the second part of the experiment: a = (-0.52m/s)/(3.25s) = -0.16m/s^2.

Now, we can use the same formula as before to find the new weight: w = mg = (m) (-0.16m/s^2) = (-3.5 x 10^-3 N)(-0.16m/s^2) = 0.56N. This is the weight of the car with the three Rayovac cells.

To find the force, momentum, KE, impulse, and work with the added cells, we can use the same formulas as before, but with the new values for mass and acceleration. For example:

Force: F = ma = (0.1kg) (-0.16m/s^2) = -0.016N
Momentum: p = mv = (0.1kg) (-0.52m/s) = -0.052kgm/s
KE: KE = (1

## 1. How do I determine the weight of an object without a scale?

There are a few methods you can use to estimate the weight of an object without a scale. One method is to use the displacement method, where you place the object in a container of water and measure the change in water level. Another method is to use the force of gravity by dropping the object and measuring its acceleration. You can also use common household items like coins or cans as reference weights to compare with the unknown object.

## 2. Can I use a bathroom scale to measure an unknown weight?

While a bathroom scale may provide a rough estimate of an object's weight, it is not a reliable method for finding an accurate weight. Bathroom scales are designed for measuring body weight and may not have a high enough weight limit or precision for measuring larger or heavier objects. It is best to use a scale specifically designed for measuring objects.

## 3. How do I convert weight from one unit to another?

To convert weight from one unit to another, you can use a conversion factor. This is a number that relates the two units of measurement. For example, to convert pounds to kilograms, you can use the conversion factor 1 pound = 0.453592 kilograms. Multiply the weight in pounds by the conversion factor to get the equivalent weight in kilograms.

## 4. What is the difference between weight and mass?

Weight and mass are often used interchangeably, but they are actually different measurements. Mass is a measure of the amount of matter in an object, while weight is the measure of the force of gravity acting on an object. Mass is typically measured in kilograms, while weight is measured in newtons. On Earth, an object's mass and weight are directly proportional to each other, but on other planets or in outer space, this may not be the case due to differences in gravity.

## 5. Can I measure the weight of an object without touching it?

Yes, there are ways to measure the weight of an object without physically touching it. One method is to use a balance scale, where you can compare the weight of the unknown object to known weights on the other side of the scale. Another method is to use a force sensor, which can measure the force of gravity acting on the object without touching it. Additionally, you can use mathematical equations, such as using the object's dimensions and density to calculate its weight.

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