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2 years ago

Help me pls its for my science class i need to show my work

Physics

1 answer:

Lostsunrise [7]2 years ago

6 0

Answer:

P = 5880 J

Explanation:

Given that,

The mass of the block, m = 30 kg

The block is sitting at a height of 20 m.

The block will have gravitational potential energy. The formula for gravitational potential energy is given by :

$P=mgh\\\\=30\times 9.8\times 20\\\\=5880\ J$

So, the required potential energy is equal to 5880 J.

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A 0.200-kg cube of ice (frozen water) is floating in glycerine.The gylcerine is in a tall cylinder that has inside radius 3.90 c

natita [175]

Answer:

Part a)

h = 0.86 cm

Part b)

Level will increase

Explanation:

Part a)

Mass of the ice cube is 0.200 kg

Now from the buoyancy force formula we know that weight of the ice is counter balanced by buoyancy force on the ice

So here we will have

$mg = \rho V_{displaced} g$

$V_{displaced} = \frac{m}{\rho}$

$V_{displaced} = \frac{0.200}{1260} = 1.59 \times 10^{-4} m^3$

now as we know that ice will melt into water

so here volume of water that will convert due to melting of ice is given as

$V\rho_w = m_{ice}$

$V = \frac{0.200}{1000} = 2\times 10^{-4} m^3$

So here extra volume that rise in the level will be given as

$\Dleta V = V - V_{displaced}$

$\pi r^2 h = 2\times 10^{-4} - 1.59 \times 10^{-4}$

$(\pi (0.039^2) h = 0.41 \times 10^{-4}$

$h = 0.86 cm$

Part b)

Since volume of water that formed here is more than the volume that is displaced by the ice so we can say that level of liquid in the cylinder will increase due to melting of ice

5 0

3 years ago

A cat falls from a table of height 1.3 m. What is the impact speed of the cat? ( i want the answer NOT THE FORMULA)

telo118 [61]

The impact speed will be
v^2 = 2*9.8*1.3
v^2 = 25.48
v= 5.04 m/s

4 0

3 years ago

Read 2 more answers

Does any part of our body vibrate when we speak ? Name the part

Nadusha1986 [10]

When YOU speak, YOUR vocal cords vibrate, sending sound waves through the air and causing MY ear drums to vibrate.

When I speak, MY vocal cords vibrate, sending sound waves through the air an causing YOUR ear drums to vibrate.

7 0

3 years ago

As a 2.0-kg object moves from (4.4 i + 5j) m to ( 11.6 i - 2j) m, the constant resultant force

fgiga [73]

Answer: $107.8\ J$

Explanation:

Given

Initial position of object is (4.4 i+5 j)

Final position of object is (11.6 i -2 j)

Force acting (4i-9j)

Work done is given by

$\Rightarrow W=F\cdot dx\\\Rightarrow W=(4i-9j)\cdot (11.6i-4.4i-2j-5j)\\\Rightarrow W=(4i-9j)\cdot (7.2i-7j)\\\Rightarrow W=28.8+63\\\Rightarrow W=91.8\ J$

Initial kinetic energy

$K_i=\dfrac{1}{2}\times 2\times 4^2\\\\K_i=16\ J$

Change in kinetic energy is equal to work done by object

$\Rightarrow K_f=K_i+W\\\Rightarrow K_f=16+91.8\\\Rightarrow K_f=107.8\ J$

5 0

3 years ago

A 3500 kg truck is parked on a 7.0∘ slope. How big is the friction force on the truck?

Arada [10]

Answer:

4180 N

Explanation:

In order to keep the truck balanced and stationary, the force of friction on the truck must be equal to the component of the weight of the truck acting parallel to the slope.

The component of the weight of the truck acting parallel to the slope is:

$mg sin \theta$

where

m = 3500 kg is the mass of the truck

g = 9.8 m/s^2 is the acceleration of gravity

$\theta=7.0^{\circ}$ is the angle of the slope

Therefore, the force of friction must be equal to

$F=(3500)(9.8)(sin 7.0^{\circ})=4180 N$

6 0

3 years ago

Read 2 more answers