Hurry need an answer

A Neglecting air resistance, a ball projected straight upward so it remains in the air for 10 seconds needs an initial speed of

ololo11 [35]

Answer:

The initial velocity is 50 m/s.

(C) is correct option.

Explanation:

Given that,

Time = 10 sec

For first half,

We need to calculate the height

Using equation of motion

$v^2=u^2+2gh$

$h =\dfrac{v^2}{2g}$ ....(I)

For second half,

We need to calculate the time

Using equation of motion

$h =ut+\dfrac{1}{2}gt_{2}^2$

$h=0+\dfrac{1}{2}gt_{2}^2$

$t_{2}=\sqrt{\dfrac{2h}{g}}$

Put the value of h from equation (I)

$t_{2}=\sqrt{\dfrac{2\times v^2}{g^2}}$

$t_{2}=\dfrac{v}{g}$

According to question,

$t_{1}+t_{2}=10$

$t_{1}=t_{2}$

Put the value of t₁ and t₂

$\dfrac{v}{g}+\dfrac{v}{g}=10$

$\dfrac{2v}{g}=10$

$v=\dfrac{10\times g}{2}$

Here, g = 10

The initial velocity is

$v=\dfrac{10\times10}{2}$

$v=50\ m/s$

Hence, The initial velocity is 50 m/s.

3 0

3 years ago

What is the momentum of an object that has a mass of 0.03 grams and a velocity of 1200 m/s2

ruslelena [56]

answer is 36

because the formulae of momentum is

mass×velocity

3 0

2 years ago

A ball is kicked horizontally from a 60 meter tall cliff at 10 m/s. How far from

o-na [289]

Hi there!

We can begin by deriving the equation for how long the ball takes to reach the bottom of the cliff.

$\large\boxed{\Delta d = v_it+ \frac{1}{2}at^2}}$

There is NO initial vertical velocity, so:

$\large\boxed{\Delta d= \frac{1}{2}at^2}}$

Rearrange to solve for time:

$2\Delta d = at^2\\\\t = \sqrt{\frac{2\Delta d}{g}}$

Plug in the given height and acceleration due to gravity (g ≈ 9.8 m/s²)

$t = \sqrt{\frac{2(60)}{(9.8)}} = 3.5 s$

Now, use the following for finding the HORIZONTAL distance using its horizontal velocity:

$\large\boxed{d_x = vt}\\\\d_x = 10(3.5) = \karge\boxed{35 m}$

6 0

3 years ago

What is the charge on a

Marrrta [24]

Answer:

positive

Explanation:

The electrons revolves around the nucleus and they are negatively charged. The nucleus consists of protons and neutrons. The neurons have no charge but the protons are positively charged.

7 0

3 years ago

Imagine a system where a block rests on an inclined plane. The block is then given an initial push so that it starts sliding dow

katen-ka-za [31]

Answer:

the correct affirmation is the 3

Explanation:

Let's analyze the problem with Newton's second law before looking at the claims.

X axis parallel to the plane, positive down

F -fr + Wₓ = ma

Y Axis perpendicular to the plane

N -Wy = 0

With trigonometry

Wₓ = W sin θ

Wy = w cos θ

Let's multiply by the displacement along the plane, to relate to the work, which has as expression W = F d

F d -fr d + Wx d = ma d

Push W₁ = Fd

frictional force W₂ = -fr d

gravity W₃ = Wx d

W₁ + W₃ -W₂ = m a d

Analysis affirmations:

R1) false. The work of gravity is the subtraction

R2) false. Each force contributes according to its magnitude

R3) true. In the equation we see that, if the acceleration is zero, W2 = W1 + W3

R4) False. It equals the difference

the correct affirmation is the 3

6 0

3 years ago