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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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Elenna [48]

It must be either speeding up, or slowing down, or turning. There are no other possibilities.

6 0
3 years ago
A ball is thrown with a speed of 20 m/s at an angle of 40o above the horizontal from the top of a 22-m tall building.
MrRissso [65]

Answer:

(a). The distance is  49.79 m.

(b). The speed of the ball is 24.39 m/s.

Explanation:

Given that,

Speed = 20 m/s

Angle = 40°

Height = 22 m

Time = 3.25 sec

(a). We need to calculate the distance

Using formula of distance

d=u\cos\theta\times t

Put the value into the formula

d=20\cos40\times3.25

d=49.79\ m

(b). We need to calculate the horizontal velocity

Using formula of velocity

v_{x}=u\cos\theta

Put the value into the formula

v_{x}=20\times\cos40

v_{x}=15.3\ m/s

We need to calculate the vertical velocity

Using equation of motion

v_{y}=u\sin\theta-gt

Put the value into the formula

v_{y}=20\sin40-9.8\times3.25

v_{y}=-19\ m/s

Negative sign shows the opposite direction.

We need to calculate the speed of ball

Using formula of speed

v=\sqrt{v_{x}^2+v_{y}^2}

v=\sqrt{(15.3)^2+(19)^2}

v=24.39\ m/s

Hence, (a). The distance is  49.79 m.

(b). The speed of the ball is 24.39 m/s.

4 0
3 years ago
In what subject could we see cross cutting concepts
meriva
A Framework for K–12 Science Education: Practices, Crosscutting Concepts, and Core Ideas (Framework) recommends science education in grades K–12 be built around three major dimensions: science and engineering practices, crosscutting concepts that unify the study of science and engineering through their common application across fields, and core ideas in the major disciplines of natural science.
4 0
3 years ago
What are successfulness of the Competition policy in South Africa?​
Mars2501 [29]

Answer:

The product choices along with its competitive prices were provided to the consumers. Practices such as horizontal collusion and resale price maintenance was declared unlawful in 1984. Prevention of monopoly growth was the aim of the competition policy act.

Explanation:

hope this helps you

6 0
3 years ago
The efficiency of a light source is the percentage of its energy input that gets radiated as visible light. if some of the blue
Anestetic [448]

The efficiency of a light source is the percentage of its energy input that gets radiated as visible light if some of the blue light in an led is used to cause a fluorescent material to glow the overall efficiency of the LED decreases.

How efficient is LED?

Different wavelengths that correlate to different visible colours are used in LED light therapy. Various shades pierce the skin at different rates.

  1. Your skin's outermost layer is impacted by blue light.
  2. Yellow light is more enveloping.
  3. Red light penetrates your skin more deeply.
  4. The deepest penetrating light is near-infrared.

Different LED hues have various effects. For instance, according to experts red LED light therapy has the potential to reduce inflammation and boost collagen formation, which declines with age and is crucial for maintaining youthful-looking skin.

Acne-causing bacteria may be destroyed by a blue LED light therapy (P. acnes).

Hence the answer is the overall efficiency of the LED decreases.

Learn more about wavelength here,

brainly.com/question/1263539

# SPJ4

7 0
2 years ago
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