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4 years ago

A ball is thrown upwards at a velocity of 20.2m/s at what time will the ball reach its highest point

1 answer:

7 0

Use the equation
$vf = vo + a \times t$
plug in the variables for the equation. Use 0 for Vf because at the highest point the velocity would be zero. Use -9.8 for acceleration because that is the speed at which gravity pulls down.
$0 = 20.2 + ( - 9.8) \times t$
your answer would be 2.06122 seconds.

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P6: An object of mass m sits on a spring of constant k in an elevator that is accelerating upwards with acceleration a. a) In te

tankabanditka [31]

Answer:

(a). The spring compressed is $\dfrac{ma+mg}{k}$ .

(b). The acceleration is 1.5 g.

Explanation:

Given that,

Acceleration = a

mass = m

spring constant = k

(a). We need to calculate the spring compressed

Using balance equation

$kx-mg=ma$

$x=\dfrac{ma+mg}{k}$ ....(I)

The spring compressed is $\dfrac{ma+mg}{k}$ .

(b). If the compression is 2.5 times larger than it is when the mass sits in a still elevator,

The compression is given by

$x=2.5\times x_{0}$

Here, acceleration is zero

So, $x=2.5\times\dfrac{mg}{k}$

We need to calculate the acceleration

Put the value of x in equation (I)

$2.5\times \dfrac{mg}{k}=\dfrac{ma+mg}{k}$

$2.5\times\dfrac{mg}{k}=\dfrac{m}{k}(a+g)$

$a=2.5g-g$

$a=1.5g$

Hence, (a). The spring compressed is $\dfrac{ma+mg}{k}$ .

(b). The acceleration is 1.5 g.

8 0

3 years ago

A jogger hears a car alarm and decides to investigate. While running toward the car, she hears an alarm frequency of 872.10 Hz.

Nata [24]

Answer:

v = 4.18 m/s

Explanation:

given,

frequency of the alarm = 872.10 Hz

after passing car frequency she hear = 851.10 Hz

Speed of sound = 343 m/s

speed of the jogger = ?

speed of the

$v_f = \dfrac{872.10-851.10}{2}$

$v_f =10.5\ Hz$

v_o = 872.1 - 10.5

$V_0 = 861.6\ Hz$

The speed of jogger

$v = \dfrac{v_1 \times 343}{v_0}-343$

$v = \dfrac{872.1 \times 343}{861.6}-343$

v = 4.18 m/s

5 0

3 years ago

Why can't a hot air balloon go to higher layers?

Elena L [17]

If you go to high you’ll run out of oxygen and possibly be blown off due to high winds.

5 0

3 years ago

A bicycle racer rides from a starting marker to a turnaround marker at 10 m/s. She then rides back along the same route from the

vitfil [10]

Answer:

12.31 m/s

Explanation:

If we recall from the previous knowledge we had about speed,

we will know that:

speed = distance/ time.

As such:

The average speed of the rider bicycle is

average speed = total distance/ total time

Mathematically, it can be computed as:

$v_{avg} = \dfrac{d+d}{\dfrac{d}{v_1}+ \dfrac{d}{v_2}}$

$v_{avg} = \dfrac{2d}{\dfrac{d}{10 \ m/s}+ \dfrac{d}{16 \ m/s}}$

$v_{avg} = \dfrac{2}{\dfrac{1}{10 \ m/s}+ \dfrac{1}{16 \ m/s}}$

$v_{avg} = \dfrac{2}{\dfrac{13}{80 \ m/s}}$

$\mathbf{v_{avg} =12.31 \ m/s}$

8 0

3 years ago

If you hold a bar magnet in each hand and bring your hands together, will the force be attractive or repulsive if the magnets ar

Law Incorporation [45]

a) The force is repulsive

b) The force is attractive

Explanation:

Every magnet has a magnetic field around it. It is possible to distinguish two different poles in the magnet, according to the direction of the magnetic field: in particular, the lines of the field go out from the North pole and go into the South Pole. When a magnet is broken, two new magnets are formed, each of them having its own north and south pole.

The force between two magnets can be either attractive or repulsive, depending on which poles are facing each other. We have the following situation:

The magnetic force between two like poles (north-north and south-south) is repulsive
The magnetic force between two opposite poles (north-south) is attractive

Therefore, we have the following situations in this problem:

Here we are holding the two north poles together: since they are like poles, they repel each other, so the force in this case is repulsive

Here we are holding a north pole and a south pole together: since they are opposite poles, they attract each other, so the force in this case is attractive

Learn more about magnetic fields:

brainly.com/question/3874443

brainly.com/question/4240735

#LearnwithBrainly

5 0

4 years ago