Hot water is poured into a mug and the mug gets hot. This is an example of which type of energy transfer?

What is the weight of a 45 kg box?

8_murik_8 [283]

45 kg.Hope it helps! :)

4 0

3 years ago

Read 2 more answers

Find the change in velocity of a 369 g hockey puck subject to the force shown below.

Elena-2011 [213]

Answer:

The change in velocity is 15.83 [m/s]

Explanation:

Using the Newton's second law we have:

ΣF = m*a

The force in the graph is 185 N, therefore:

$185=0.369*a\\Where\\a=acceleration made it by the force [m/s^2]$

$a=501.35[m/s^2]$

Now using the following kinematic equation:

$V^{2}=Vi^{2} + 2*a*(x-xi) \\where\\V=final velocity [m/s]\\Vi= initial velocity [m/s] = 0 the hockey disk is in rest when receives the hit.\\ x = Final position [m] = 0.4 m\\xi = initial position [m] = 0.15m\\$

Now replacing the values:

$V^{2}=0 + 2*501.35*(0.4-0.15)\\ \\V= 15.83[m/s]$

3 0

3 years ago

A Pitot-static tube is mounted on a 2.5 cm pipe where oil (???? = 860 kg/m3, ???? = 0.0103 kg/m·s) is flowing. The Pitot tube is

emmasim [6.3K]

Answer:

$\dot{V}=0.0733 \,m^3.s^{-1}$

Explanation:

Given:

density, $\rho=860\,kg.m^{-3}$

diameter of the pipe, $d=2.5\times 10^{-2}m$

pressure difference, $\Delta P=95.8\times 10^{5}\,Pa$

In case of pitot tube, the velocity is given by:

$v=\sqrt{\frac{2.\Delta P}{\rho} }$

$v=\sqrt{\frac{2\times 95.8\times 10^{5}}{860} }$

$v=149.26\,m.s^{-1}$

Now we know that volumetric flow rate is given as:

$\dot{V}=a.v$

where :

a= cross sectional area of the pipe

v= velocity of flow

$\dot{V}=(\pi\times \frac{(2.5\times 10^{-2})^2}{4} ) \times 149.26$

$\dot{V}=0.0733 \,m^3.s^{-1}$

4 0

3 years ago

Starting from rest, a disk rotates about its central axis with constant angular acceleration. In 8.0 s, it rotates 35 rad.

Harman [31]

Answer:

(a) 1.093 rad/s^2

(b) 4.375 rad/s

(c) 8.744 rad/s

(d) 67.845 rad

Explanation:

initial angular velocity, ωo = 0

time, t = 8s

angular displacement, θ = 35 rad

(a) Let α be the angular acceleration.

Use second equation of motion for rotational motion

$\theta =\omega _{0}t+\frac{1}{2}\alpha t^{2}$

By substituting the values

35 = 0 + 0.5 x α x 8 x 8

α = 1.093 rad/s^2

(b) The average angular velocity is defined as the ratio of total angular displacement to the total time taken .

Average angular velocity = 35 / 8 = 4.375 rad/s

(c) Let ω be the instantaneous angular velocity at t = 8 s

Use first equation of motion for rotational motion

ω = ωo + αt

ω = 0 + 1.093 x 8 = 8.744 rad/s

(d) Let in next 5 seconds the angular displacement is θ.

$\theta =\omega _{0}t+\frac{1}{2}\alpha t^{2}$

By substituting the values

θ = 8.744 x 5 + 0.5 x 1.093 x 5 x 5

θ = 67.845 rad

8 0

4 years ago

A helicopter flies 168 miles against the wind in 2 hours; with the wind, it can fly 252 miles in the same amount of time. find t

posledela

Let $v_h$ be the speed of the helicopter in still air. Let $v_w$ be the speed of the wind. Then, from the given information,

$(v_h-v_w)2=168\\ (v_h+v_w)2=252\\$

Adding the above 2 equations,

$4v_h=168+252\\ 4v_h=420\\ v_h=105$

The speed of the helicopter in still air $105 \;mi/hour$

6 0

3 years ago

Read 2 more answers