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3 years ago

8

Three rocks are rolling down a hill at the same speed. Rock 1 has a mass of 1 kg, rock 2 has a mass of 1.5 kg, and rock 3 has a

mass of 3 kg. Which rock has the most kinetic energy?

1 answer:

klio [65]3 years ago

5 0

Heaviest one always have the most kinetic E. for example, Didier drogba was running then nobody can stop him cuz his heavyyyyyy

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3. An athlete makes a long jump and follows a projectile motion. Air resistance is negligible. Which one of the following statem

yulyashka [42]

Answer:

Option (b) is correct.

Explanation:

The motion under the influence of gravity is called projectile motion.

The acceleration due to gravity is constant through out the motion and it is always acting downwards.

When an athlete jumps and follow the projectile path, it always have the same horizontal velocity as there is no acceleration in the horizontal direction.

Also he has the vertical acceleration constant which is equal to the acceleration due to gravity and acts towards the center of earth.

Option (b) is correct.

6 0

3 years ago

A 94.7 kg horizontal circular platform rotates freely with no friction about its center at an initial angular velocity of 1.75 r

Marta_Voda [28]

Answer:

The angular velocity of the platform is 1.114 rad/s.

Explanation:

Step 1: Given data

Mass of the horizontal circular platform = 94.7 kg

Mass of the monkey = 21.1 kg

Initial angular velocity = 1.75 rad/s

A monkey drops a 9.25 kg bunch of bananas

They hit the platform at 4/5 of its radius from the center

Model the platform as a disk of radius 1.63 m

Step 2: Calculate the moment of inertia of the disk

I = ½ * m * r² = ½ * 94.7 * 1.63² = 125.80

Step 3: Calculate the initial angular momentum

I = 125.80 * 1.75 = 220.15

Step 4: Calculate the moment of inertia for the bananas

For the bananas, r = 4/5 * 1.63 = 1.304 m

I = 9.25 * 1.304² = 15.73

Step 5: Calculate Moment of inertia for the monkey

I = 21.1 * 1.63² = 56.06

Step 6: Total moment of inertia = 125.80 + 15.73 + 56.06 = 197.59

Step 7: Calculate final angular momentum = 197.59 * ω

197.59 * ω = 220.15

ω = 220.15 / 197.59

This is approximately 1.114 rad/s.

3 0

3 years ago

Mt. Asama, Japan, is an active volcano. In 2009, an eruption threw solid volcanic rocks that landed 1 km horizontally from the c

Nata [24]

Answer:

a) 69.3 m/s

b) 18.84 s

Explanation:

Let the initial velocity = u

The vertical and horizontal components of the velocity is given by uᵧ and uₓ respectively

uᵧ = u sin 40° = 0.6428 u

uₓ = u cos 40° = 0.766 u

We're given that the horizontal distance travelled by the projectile rock (Range) = 1 km = 1000 m

The range of a projectile motion is given as

R = uₓt

where t = total time of flight

1000 = 0.766 ut

ut = 1305.5

The vertical distance travelled by the projectile rocks,

y = uᵧ t - (1/2)gt²

y = - 900 m (900 m below the crater's level)

-900 = 0.6428 ut - 4.9t²

Recall, ut = 1305.5

-900 = 0.6428(1305.5) - 4.9 t²

4.9t² = 839.1754 + 900

4.9t² = 1739.1754

t = 18.84 s

Recall again, ut = 1305.5

u = 1305.5/18.84 = 69.3 m/s

7 0

3 years ago

How is the sun related to nuclear electromagnetic and heat energy?

erik [133]

The sun creates nuclear energy in it's core and as a byproduct heat is created. It gives this off in the form of heat and radiation.

7 0

3 years ago

A flea jumps straight up to a maximum height of 0.400 m . what is its initial velocity v0 as it leaves the ground?

timama [110]

For an object`s motion, the Kinematic equation is,

$v^2=v_{0}^2+2ah$

Here, v is the final velocity and h is stands for the height of the object and a is the acceleration of the object.

As according to question,

$v=0m/s,a=g-9.8 m/s^2$ and $h = 0.400 m$

Thus, putting these values in above equation, we get

$0= v_{0}^2 -2gh$

or

$v_{0} =\sqrt{2 \times 9.8 \times 0.400 }$

$v_{0} = 2.8 m/s$

Therefore, initial velocity is 2.8 m/s

8 0

3 years ago