I need c only please answer it

A pendulum consists of a 2.0-kg block hanging on a 1.5-m length string. A 10-g bullet moving with a horizontal velocity of 900 m

pav-90 [236]

Answer:

The maximum height above its initial position is:

$h_{max}=1.53\: m$

Explanation:

Using momentum conservation:

$m_{b}v_{ib}=m_{B}v_{fB}+m_{b}v_{fb}$ (1)

Where:

m(b) is the mass of the bullet
m(B) is the mass of the block
v(ib) is the initial velocity of the bullet
v(fb) is the final velocity of the bullet
v(fB) is the final velocity of the block

Let's find v(fb) using equation (1)

$m_{b}(v_{ib}-v_{fb})=m_{B}v_{fB}$

$v_{fB}=\frac{m_{b}(v_{ib}-v_{fb})}{m_{B}}$

$v_{fB}=\frac{0.1(900-300)}{2}$

$v_{fB}=30\: m/s$

We need to find the maximum height, it means that all kinetic energy converts into gravitational potential energy.

$\frac{1}{2}m_{B}v_{fB}=m_{B}gh_{max}$

$h_{max}=\frac{1}{2g}v_{fB}$

$h_{max}=\frac{1}{2(9.81)}30$

$h_{max}=1.53\: m$

I hope it helps you!

8 0

3 years ago

Which of the following changes will always increase the efficiency of a thermodynamic engine? Choose all correct statements.

Ilya [14]

Answer:B,C,D

Explanation:

Thermodynamic efficiency is given by

$\eta =1-\frac{T_C}{T-H}$

$\eta$ efficiency can be increased by Keeping $_c$ constant and increasing $T_H$

Keeping $T_H$ constant and decreasing $T_c$

by increasing $\Delta T=T_H-T_c$

by decreasing $\frac{T_C}{T_H}$ ratio

5 0

3 years ago

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Consider a small child sliding down two differently shaped slides that have the same coefficient of kinetic friction. How must t

timama [110]

Answer:

Having a bigger angle above the horizontal

Explanation:

Applying the energy conservation theorem:

$K_1+U_1+W_{ext}=K_2+U_2$

The kinetic energy is reduced because of the work done by the friction force.

The friction force is given by:

$F_f=F_N*\µ$

so the friction force depends on the Normal force, because the slide has an angle the normal force is given by:

$F_N=m.g*cos(\theta)$

So when the angle of the slide is bigger, the friction force decreases, for example:

for 45 degrees:

$F_N=m.g*cos(45)\\F_N=0.70(m.g)\\$

for 75 degrees:

$F_N=m.g*cos(75)\\F_N=0.26(m.g)\\$

as you can see if the angle is bigger above the horizontal, the friction force is reduced and so the work done by that force. We didn't have to change the height of the slide, so the potential gravitational energy remains the same.

6 0

3 years ago

Kinetic energy is the energy an object has due to its

lara31 [8.8K]

Answer:

potential energy or stored energy

Explanation:

6 0

3 years ago

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3) If an airplane is in flight cruising at constant velocity, what can be said about the net work

Crazy boy [7]

Explanation:

<h3>In physics, constant velocity occurs when there is no net force acting on the object causing it to accelerate. In terms of airplane flight, the two main forces influencing its velocity forward are drag and thrust. At a constant altitude, when the force of thrust equals the opposing force of drag, then the airplane will experience uniform motion in one direction. This can be further explained by Newton’s First Law. </h3>

6 0

3 years ago