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alukav5142 [94]

3 years ago

11

A bicycle and its rider have a combined mass of 80 kg and a speed of 6 m/s. What is the magnitude of the average force needed to

bring the bicycle and its rider to a stop in 4 seconds?

2 answers:

anygoal [31]3 years ago

6 0

Answer: 120N

Explanation:Please see attachment for explanation

lisabon 2012 [21]3 years ago

4 0

The magnitude is 24 meter

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What do protoplanets eventually grow into?

kow [346]

Answer:

a planet

Explanation:

If planetesimals, objects that combined to form protoplanets, were to collide head on in the early solar nebula, they would shatter to the point where they would be unable to grow into a larger size, a protoplanet. A protoplanet is a massive object that will eventually become a planet.

7 0

2 years ago

Consider a system of two particles: ball A with a mass m is moving to the right a speed 2v and ball B with a mass 3m is moving t

arlik [135]

Answer:

Explanation:

Answer:

Explanation:

Given that,

System of two particle

Ball A has mass

Ma = m

Ball A is moving to the right (positive x axis) with velocity of

Va = 2v •i

Ball B has a mass

Mb = 3m

Ball B is moving to left (negative x axis) with a velocity of

Vb = -v •i

Velocity of centre of mass Vcm?

Velocity of centre of mass can be calculated using

Vcm = 1/M ΣMi•Vi

Where M is sum of mass

M = M1 + M2 + M3 +...

Therefore,

Vcm=[1/(Ma + Mb)] × (Ma•Va +Mb•Vb

Rearranging for better understanding

Vcm = (Ma•Va + Mb•Vb) / ( Ma + Mb)

Vcm = (m•2v + 3m•-v) / (m + 3m)

Vcm = (2mv — 3mv) / 4m

Vcm = —mv / 4m

Vcm = —v / 4

Vcm = —¼V •i

3 0

3 years ago

A car starts from rest and travels for 5.0 s with a uniform acceleration of +1.5 m/s2 . The driver then applies the brakes, caus

Svetlanka [38]

The final velocity of the car is +1.5 m/s.

Explanation:

We have to divide the problem into two parts.

In the first part, the car starts from rest and accelerates for 5.0 s. We can find the final velocity of the car after this first part using the suvat equation:

$v = u +at$

where

v is the final velocity

u = 0 is the initial velocity

$a=+1.5 m/s^2$ is the acceleration

t = 5.0 s is the time

Substituting,

$v=0+(1.5)(5.0)=7.5 m/s$

In the second part, the brakes are applied, so the car decelerates for 3.0 s, and the final velocity is given by

$v' = v + at$

where

v' is the final velocity

v = 7.5 m/s is the velocity at the beginning of this part

$a=-2.0 m/s^2$ is the deceleration

t = 3.0 s is the time

Substituting,

$v'=7.5+(-2.0)(3.0)=+1.5 m/s$

So, the final velocity is +1.5 m/s.

Learn more about accelerated motion:

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7 0

3 years ago

Find the heat energy is required to change 2Kg of ice at 0 C to water at 20 C ( specific latent heat of fusion of water = 336000

katrin2010 [14]

We want to find the energy that we need to transform 2kg of ice at 0°C to water at 20°C.

We will find that we must give 840,000 Joules.

First, we must change of phase from ice to water.

We use the specific latent heat of fusion to do this, this quantity tells us the amount of energy that we need to transform 1 kg of ice into water.

So we need 336,000 J of energy to transform 1kg of ice into water, and there are 2kg of ice, then we need twice that amount of energy:

2*336,000 J = 672,000 J

Now we have 2kg of water at 0°C, and we need to increase its temperature to 20°C.

Here we use the specific heat, it tell us the amount of energy that we need to increase the temperature per mass of water by 1°C.

We know that:

specific heat of capacity of water = 4200 J/kg°C

This means that we need to give 4,200 Joules of energy to increase the temperature by 1°C of 1kg of water.

Then to increase 1°C of 2kg of water we need twice that amount:

2*4,200 J = 8,400 J

And that is for 1°C, we need to give that amount 20 times (to increase 20°C) this is:

20*8,400 J = 168,000 J

Then the total amount of energy that we must give is:

E = 672,000 J + 168,000 J = 840,000 J

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5 0

3 years ago

Three objects lie in the x, y plane. Each rotates about the z axis with an angular speed of 5.58 rad/s. The mass m of each objec

QveST [7]

Answer:

a) V1=11.05m/s V2=92.07m/s V3=17.24m/s

b) KE = 16238.26J

Explanation:

For tangential speeds:

$V1 = \omega*R1=5.58*1.98=11.05m/s$

$V2 = \omega*R2=5.58*16.5=92.07m/s$

$V3 = \omega*R3=5.58*3.09=17.24m/s$

For the kinetic energy, it can be calculated as:

$KE=1/2*\omega^2*(I1+I2+I3)$

Where:

$I1 = m1*R1^2=5.46*1.98^2=21.4kg.m^2$

$I2 = m2*R2^2=3.64*16.5^2=990.99kg.m^2$

$I3 = m3*R3^2=3.21*3.09^2=30.65kg.m^2$

So,

$KE=1/2*5.58^2*(21.4+990.99+30.65)$

KE=16238.26J

4 0

3 years ago