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2 years ago

A footballer kicks a football of mass 430 g and it flies off at a speed of 8 m/s. What is the KE of the football?

Physics

1 answer:

klasskru [66]2 years ago

3 0

Answer:

13.76 Joules

Explanation:

The SI units for joules are defined to be kilogram*meters per second. Therefore, we must turn the grams to kilograms by dividing the answer by 1,000. This is due to 1,000 grams being in a single kilogram. Kinetic energy is defined to be:

$KE=\frac{1}{2} mv^2$

Therefore:

$KE=\frac{1}{2} (0.43kg)(8m/s)^2=13.76J$

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Assuming a vertical trajectory with no drag, derive the applicable form of the rocket equation for this application

VARVARA [1.3K]

Answer:

The vertical trajectory is governed by Ordinary Differential Equation.

Time derivatives of each state variables.

d(d)/dt = v, d(m)/dt = -d(m-fuel)/dt, d(v)/dt = F/m.

Where V is velocity positive upwards, t is time, m is mass, m-fuel is fuel mass, F is Total force, positive upwards.

Therefore,

F = -mg - D + T, If V is positive and

F = -mg + D - T, If T is negative.

D is drag and the questions gave it as zero.

Explanation:

The two sign cases in derivative equations above are required because F is defined positive up, so the drag D and thrust T can subtract or add to F depending in the sign of V . In contrast, the gravity force contribution mg is always negative. In general, F will be some function of time, and may also depend on the characteristics of the particular rocket. For example, the T component of F will become zero after all the fuel is expended, after which point the rocket will be ballistic, with only the gravity force and the aerodynamic drag force being p

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3 years ago

3. A 900N mountain climber scales a

Umnica [9.8K]

Answer:

Explanation:

The work done by an object can be found by using the formula

workdone = force × distance

From the question we have

workdone = 900 × 150

We have the final answer as

Hope this helps you

4 0

2 years ago

What happens to the water particles in a wave?

lys-0071 [83]

Answer: waves transport energy, not water. As a wave crest passes, the water particles move in circular paths. The movement of the floating inner tube is simulacra to the movement of the water particles. Water particles rise as a wave crest approaches.

Explanation:

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3 years ago

Read 2 more answers

John and Caroline go out for a walk one day. This graph represents their distance from home.

Serga [27]

Answer:

Option C is the correct answer.

Explanation:

We have velocity of a body = Change in position/ Time.

Considering first portion of graph,

Change in position = 30 - 0 = 30 m

Time = 0.75 hours = 45 minutes = 2700 seconds

Velocity = 30/2700 = 0.011 m/s

Considering second portion of graph,

Change in position = 30 - 30 = 0 m

Time = 0.5 hours = 30 minutes = 1800 seconds

Velocity = 0/1800 = 0 m/s

Considering third portion of graph,

Change in position = 0 - 30 = -30 m

Time = 0.75 hours = 45 minutes = 2700 seconds

Velocity = -30/2700 = -0.011 m/s

So firstly they walked in one direction(positive direction), then they were still(velocity is zero), then they walked in the opposite direction( velocity is negative).

Option C is the correct answer.

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3 years ago

Read 2 more answers

If the mass of the moon is ...

bulgar [2K]

C decreased the factor cuz the max is smaller

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3 years ago