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A 3.03 kg briefcase is sitting at rest on a level floor. The acceleration of gravity is 9.81 m/s 2 . a) What is its acceleration

Blizzard [7]

Answer:

a) a = 0

b) W = 29.72 N

Explanation:

a)The acceleration of an object is defined as the change of its speed with respect to a time interval, Because the briefcase remains at rest, its acceleration (a) is zero.

a=0

b) Calculation of the weight of the briefcase

The formula to calculate the weight is the following:

W= m*g Formula (1)

Where:

W : is the weight in Newtons (N)

m : is the mass in kilograms (kg)

g : is the acceleration due to gravity in meters over second square (m/s²)

Data

m=3.03 kg : mass of the briefcase

m=9.81 m/s² : acceleration due to gravity

We replace data in the formula (1)

W= m*g = 3.03 kg * 9.81 m/s²

W= 29.72 N

6 0

4 years ago

Use the work-energy theorem to determine the force required to stop a 1000 kg car moving at a speed of 20.0 m/s if there is a di

Vlad1618 [11]

Answer:

4.44 kN in the opposite direction of acceleration.

Explanation:

Given that, the initial speed of the car is, $u=20m/s$

And the mass of the car is, $m=1000 kg$

The total distance covered by the car before stop, $s=45m$

And the final speed of the car is, $u=0m/s$

Now initial kinetic energy is,

$KE_{i}=\frac{1}{2}mu^{2}$

Substitute the value of u and m in the above equation, we get

$KE_{i}=\frac{1}{2}(1000kg)\times (20)^{2}\\KE_{i}=20000J$

Now final kinetic energy is,

$KE_{f}=\frac{1}{2}mv^{2}$

Substitute the value of v and m in the above equation, we get

$KE_{f}=\frac{1}{2}(1000kg)\times (0)^{2}\\KE_{i}=0J$

Now applying work energy theorem.

Work done= change in kinetic energy

Therefore,

$F.S=KE_{f}-KE_{i}\\F\times 45=(0-200000)J\\F=\frac{-200000J}{45}\\ F=-4444.44N\\F=-4.44kN$

Here, the force is negative because the force and acceleration in the opposite direction.

6 0

3 years ago

Water is pouring into a conical tank at the rate of 8 cubic feet per minute. If the height of the tank is 10 feet and the radius

iren [92.7K]

Answer:

$\frac{25}{8\pi}ft/min$

Explanation:

We are given that

$\frac{dV}{dt}=8 ft^3/min$

Height of tank=h=10 ft

Radius of tank, r=4 feet

We have to find the dh/dt when the water is 4 feet deep.

$\frac{r}{h}=\frac{4}{10}=\frac{2}{5}$

$r=\frac{2}{5}h$

Volume of cone , $V=\frac{1}{3}\pi r^2 h$

Substitute the values

Volume of cone , $V=\frac{1}{3}\pi(\frac{2}{5}h)^2h=\frac{4}{75}\pi h^3$

Differentiate w.r.t t

$\frac{dV}{dt}=\frac{12}{75}\pi\times h^2\times \frac{dh}{dt}$

Substitute the values

$8=\frac{12}{75}\times\pi (4)^2\times \frac{dh}{dt}$

$\frac{dh}{dt}=\frac{8\times 75}{12\times 16\pi}=\frac{25}{8\pi}ft/min$

3 0

4 years ago

The Cosmoclock 21 Ferris wheel in Yokohama City, Japan, has a diameter of 100 m. Its name comes from its 60 arms, each of which

Slav-nsk [51]

Answer:

V = 5.24m/s

Explanation:

See attachment below.

5 0

4 years ago

How do plant and animal cells function differently

e-lub [12.9K]

Although, the overall function of the cell is the same, there are some important differences between animal and plant cells. The first difference is that plant cells have an organelle called chloroplast. Chloroplasts contain a pigment called chlorophyll (which gives the plant its green color).

Centrosomes and lysosomes are found in animal cells, but do not exist within plant cells.The lysosomes are the animal cell's "garbage disposal", while in plant cells the same function takes place in vacuoles.Plant cells have a cell wall, chloroplasts and other specialized plastids, and a large central vacuole, which are not found within animal cells.

Source: Boundless. “Comparing Plant and Animal Cells.” Boundless Biology Boundless, 26 May. 2016. Retrieved 10 Dec. 2016 from https://www.boundless.com/biology/textbooks/boundless-biology-textbook/cell-structure-4/eukaryotic-c...

7 0

3 years ago