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dangina [55]
3 years ago
10

A 2kg watermelon is dropped from a 4m tall roof a) use the appropriate kinematic equations to determine the instantaneous veloci

ty of the watermelon as its strikes the ground below?
Physics
1 answer:
Ivenika [448]3 years ago
6 0

Answer:

8.85m/s

Explanation:

The potential energy the watermelon held before dropping is Ep=mgh=2*9.8*4=78.4J.

When it strikes the ground, all of its Ep will transfer into Ek, so 1/2*m*v^2=78.4.

We already knew that m=2, so insert that in, we will get the V^2=78.4 m/s, V=8.85 m/s

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Number these from least (1) to most (5) inertia.
worty [1.4K]

Answer:

 1. A feather

2. A baseball

3. a small car

4. A truck

5. A large train

Explanation:

5 0
2 years ago
Read 2 more answers
Earth is about 150 million kilometers from the Sun, and the apparent brightness of the Sun in our sky is about 1300 watts/m2. Us
nalin [4]

Answer:

13 W/m^2

Explanation:

The apparent brightness follows an inverse square law, therefore we can write:

I \propto \frac{1}{r^2}

where I is the apparent brightness and r is the distance from the Sun.

We can also rewrite the law as

\frac{I_2}{I_1}=\frac{r_1^2}{r_2^2} (1)

where in this problem, we have:

I_1 = 1300 W/m^2 apparent brightness at a distance r_1, where

r_1 = 150 million km

We want to estimate the apparent brightness at r_2, where r_2 is ten times r_1, so

r_2 = 10 r_1

Re-arranging eq.(1), we find I_2:

I_2 = \frac{r_1^2}{r_2^2}I_1 = \frac{r_1^2}{(10r_1)^2}(1300)=\frac{1}{100}(1300)=13 W/m^2

5 0
3 years ago
The overall length of a piccolo is 32.0 cm. The resonating air column vibrates as in a pipe that is open at both ends. (a) Find
lana66690 [7]

Answer:

lowest frequency = 535.93 Hz

distance  between adjacent anti nodes is 4.25 cm

Explanation:

given data

length L = 32 cm = 0.32 m

to find out

frequency and distance between adjacent anti nodes

solution

we consider here speed of sound through air at room temperature 20 degree is  approximately  v = 343 m/s

so

lowest frequency will be = \frac{v}{2L}   ..............1

put here value in equation 1

lowest frequency will be = \frac{343}{2(0.32)}

lowest frequency = 535.93 Hz

and

we have given highest frequency f = 4000Hz

so

wavelength =  \frac{v}{f}   ..............2

put here value

wavelength =  \frac{343}{4000}  

wavelength = 0.08575 m

so distance =  \frac{wavelength}{2}   ..............3

distance =  \frac{0.08575}{2}  

distance = 0.0425 m

so distance  between adjacent anti nodes is 4.25 cm

3 0
3 years ago
What work do you think is done when you carry a 20 N weight backpack for a 1000 m walk? will the work be positive, negative, or
dezoksy [38]

The work done is positive and is equal to 20000 J

<h3>What is work done?</h3>

Work done is defined as the product of force and the distance moved by the force.

Mathematically:

  • Work done = force * distance

The work done by the force = 20 * 1000 = 20000J

The work done is positive and is equal to 20000 J

Learn more about work done at: brainly.com/question/25923373

#SPJ1

8 0
2 years ago
A car is driving at 85 km/h and the driver spots a stop sign ahead. What coefficient of friction is needed to stop the car at th
almond37 [142]

Answer:

μ = 0.0315

Explanation:

Since the car moves on a horizontal surface, if we sum forces equal to zero on the Y-axis, we can determine the value of the normal force exerted by the ground on the vehicle. This force is equal to the weight of the cart (product of its mass by gravity)

N = m*g (1)

The friction force is equal to the product of the normal force by the coefficient of friction.

F = μ*N (2)

This way replacing 1 in 2, we have:

F = μ*m*g (2)

Using the theorem of work and energy, which tells us that the sum of the potential and kinetic energies and the work done on a body is equal to the final kinetic energy of the body. We can determine an equation that relates the frictional force to the initial speed of the carriage, so we will determine the coefficient of friction.

\frac{1}{2} *m*v_{i}^{2}-(F*d)=  \frac{1}{2} *m*v_{f}^{2}

where:

vf = final velocity = 0

vi = initial velocity = 85 [km/h] = 23.61 [m/s]

d = displacement = 900 [m]

F = friction force [N]

The final velocity is zero since when the vehicle has traveled 900 meters its velocity is zero.

Now replacing:

(1/2)*m*(23.61)^2 = μ*m*g*d

0.5*(23.61)^2 = μ*9,81*900

μ = 0.0315

5 0
3 years ago
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