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My name is Ann [436]

3 years ago

11

a person is sitting on the last bench can see clearly see things written on book but cannot see them distinctly on board. what t

ypes of lens is this concave or convex

1 answer:

marysya [2.9K]3 years ago

7 0

Answer:

I think concave

Explanation:

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I WILL MARK YOU AS BRAINLIEST IF RIGHT The fastest pitch ever recorded in MLB was thrown by Aroldis Chapman at 5 points 105.1 mp

Goshia [24]

Answer: The force was 13.92 Newtons.

Explanation:

First, let's recall the second Newton's law:

The net force is equal to the mass times the acceleration, or:

F = m*a

where:

F = force

m = mass

a = acceleration.

When the player hits the ball with the bat, he applies a force that accelerates the ball for a small period of time, that increases greatly the speed of the ball.

In this case, we know that:

the mass of the ball is 0.145 kg

The acceleration of the ball is 96m/s^2

Then we can input those values in the above equation to find the force.

F = 0.145kg*96m/s^2 = 13.92 N

The force was 13.92 Newtons.

5 0

3 years ago

A young kid of mass m = 36 kg is swinging on a swing. The length from the top of the swing set to the seat is L = 3.5 m. The boy

lara31 [8.8K]

Answer:

Explanation:

Given

mass of boy=36 kg

length of swing=3.5 m

Let T be the tension in the swing

At top point $mg-T=\frac{mv^2}{r}$

where v=velocity needed to complete circular path

Th-resold velocity is given by $mg-0=\frac{mv^2}{r}$

$v=\sqrt{gr}=\sqrt{9.8\times 3.5}=5.85 m/s$

So apparent weight of boy will be zero at top when it travels with a velocity of $v=\sqrt{gr}$

To get the velocity at bottom conserve energy at Top and bottom

At top $E_T=mg\times 2L+\frac{mv^2}{2}$

Energy at Bottom $E_b=\frac{mv_0^2}{2}$

Comparing two as energy is conserved

$v_0^2=4gl+gl$

$v_0^2=5gL$

$v_0=\sqrt{5gL}=13.09 m/s$

Apparent weight at bottom is given by

$W=\frac{mv_0^2}{L}-mg=\frac{36\times 13.09^2}{3.5}+36\times 9.8=2115.23 N$

6 0

3 years ago

Can you help me??????????????????????????)?

garik1379 [7]

Answer:

Velocity is a change in displacement over change in time and uses the units m/s.

Both are rates of change and can be positive or negative.

Acceleration is a change in velocity over change in time and uses the units m/s².

Explanation:

Velocity is the change in displacement over change in time, this makes it a rate of change. It can be positive or negative because it is a vector quantity. It uses the units m/s because that is a displacement unit over a time unit.

Acceleration is the change in velocity over change in time, this makes it a rate of change. It can be positive or negative because it is also a vector quantity. It uses the units m/s² (m/s/s) because that is a velocity unit over a time unit.

5 0

3 years ago

If the Sun were to stop shining, Earth would stop receiving heat and light within about eight minutes. Earth, however, would rem

hjlf

If<span> The </span>Sun<span> Went Out, How Long </span>Could<span> Life On </span>Earth<span> Survive? ... (which is actually physically impossible), the </span>Earth would stay<span> warm—at least ... from the planet's core </span>would<span> equal the</span>heat<span> that the </span>Earth<span> radiates into space, ... Photosynthesis </span>would<span> halt immediately, and </span>most<span> plants</span>would<span> die </span>in<span> a few </span>weeks<span>.</span>

6 0

3 years ago

Read 2 more answers

A small fish is dropped by a pelican that is rising steadily at 0.50 m/s.

natima [27]

Answer:

(a) 24.025 m/s. downward.

(b) 31 m

Explanation:

From Newton's equation of motion,

(a)

v = u + gt ................... Equation 1

Where v = final velocity, u = initial velocity, g = acceleration due to gravity, t = time.

Note: Let upward velocity be negative and downward be positive

Given: u = -0.5 m/s (upward), t = 2.5 s

Constant : g = 9.81 m/s²

Substitute into equation 1

v = 0.5+9.81(2.5)

v = -0.5+24.525

v = 24.025 m/s. downward.

(b) using

s₁ = ut + 1/2gt²......................... Equation 2

Where s₁ = distance at which the fish fall after being dropped by the pelican

Given: u = - 0.5 m/s, t = 2.5 s, g = 9.81 m/s²

Substitute into equation 2

s₁ = -0.5(2.5) + 1/2(9.81)(2.5)²

s₁ = -1.25+30.656

s₁ = 29.41 m

also,

s₂ = vt ................ Equation 3

Where s₂ = the distance by which the pelican rise during this time.

Given: v = 0.5 m/s, t= 2.5 s

s₂ = 0.5(2.5)

s₂ = 1.25 m.

Note: Distance between the pelican and fish = s₁ + s₂

Distance between the pelican and fish = 29.41+1.25

Distance between the pelican and fish = 30.66

Distance between the pelican and fish ≈ 31 m

3 0

3 years ago