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Paladinen [302]

3 years ago

14

. A child drops a ball from a window. The ball strikes the ground in 3.0 seconds. What is the. A child drops a ball from a windo

w. The ball strikes the ground in 3.0 seconds. What is the
velocity of the ball the instant before it hits the ground?

1 answer:

Vsevolod [243]3 years ago

3 0

Answer:

30m/s

Explanation:

Use formula for height calculation: Time = √2h/√g
From here calculate height which comes out to be: 45m(if g is taken 10)
Then use formula for velocity calculation: v = √2gh

The velocity comes out to be 30m/s

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What are the main ideas of physical science

Mademuasel [1]

Hysical science is defined as the study of observable phenomena in the universe.

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<span>this method states: </span>

<span>observe a "real" ( not imaginary ) phenomena. </span>

<span>make a hypothesis ( or theory / idea ) that EXPLAINS this phenomena. </span>

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3 0

2 years ago

the force between your feet and the floor is greater while standing on your tiptoes than while standing flat on your feet

Elodia [21]

Yes thats correct....becuase all of your weight is concentrated on a small area compared to the larger surface area of your feet!
is that what your question was?

4 0

2 years ago

Read 2 more answers

If he leaves the ramp with a speed of 31.0 m/s and has a speed of 29.5 m/s at the top of his trajectory, determine his maximum h

raketka [301]

Answer:

The maximum height reached is 4.63 m.

Explanation:

Given:

Initial speed of the man (u) = 31.0 m/s

Speed at the top of trajectory ( $u_x$ ) = 29.5 m/s

Acceleration due to gravity (g) = 9.8 m/s²

When the man reaches the top of the trajectory, the vertical component of velocity becomes zero and hence only horizontal component of velocity acts on him.

Also, since there is no net force acting in the horizontal direction, the acceleration is zero in the horizontal direction from Newton's second law. Thus, the horizontal component of velocity always remains the same.

So, speed at the top of trajectory is nothing but the horizontal component of initial velocity.

Now, initial velocity can be rewritten in terms of its components as:

$u^2=u_x^2+u_y^2$

Where, $u_x\ and\ u_y$ are the initial horizontal and vertical velocities of the man.

Now, plug in the given values and simplify. This gives,

$(31.0)^2=(29.5)^2+u_y^2\\\\961=870.25+u_y^2\\\\u_y^2=961-870.25\\\\u_y^2=90.75\ m^2/s^2--------1$

Now, we know that, for a projectile motion, the maximum height is given as:

$H=\frac{u_y^2}{2g}$

Plug in the value from equation (1) and 9.8 for 'g' to solve for 'H'. This gives,

$H=\frac{90.75}{2\times 9.8}\\\\H=4.63\ m$

Therefore, the maximum height reached is 4.63 m.

3 0

3 years ago

An object of mass 0.40 kg, hanging from a spring with a spring constant of 8.0 N/m, is set into an up-and-down simple harmonic m

Sergeeva-Olga [200]

Answer:

a = 2 m/s2

Explanation:

we know from newtons 2nd law

F = ma.

we also know that from hookes law we have

F = kx

equate both value of force to get value of acceleration

kx = ma,

where,

k is spring constant = 8.0 N/m

x is maximum displacement 0.10 m

m is mass of object 0.40 kg

a = \frac{kx}{m}

= \frac{8 *0 .10}{0.40}

a = 2 m/s2

5 0

3 years ago

jok3333 [9.3K]

Answer:

X: Low potential energy

Y: High Potential energy

Z: Flow of electrons

Explanation: From the figure, it's obvious that Z is the flow of electrons, as shown by the arrow demonstrating the direction of the flow. Because of this, we can easily nullify choices B and C.

From the figure, we can notice that Y has more energy stored and X has a lot less, so you can conclude that Y has high potential energy while X has low potential energy.

8 0

3 years ago