Please need help with ? Number 20

A 0.060-kg ice hockey puck comes toward a player with a high speed. The player hits it directly back softly with an average forc

kramer

Answer:u=-22 m/s

Explanation:

Given

mass of puck $m=0.06\ kg$

Average force $f_{avg}=1.5\times 10^3\ N$

time of contact $t=1.2ms=1.2\times 10^{-3}\ s$

puck leaves with a velocity of $v=8\ m/s$

We know impulse is $F_{avg}\Delta t$ $=\text{change in momentum}$

therefore

$1.5\times 10^3\times (1.2\times 10^{-3})=P_f-P_i$

$P_i=0.06\times 8-1.8$

$P_i=0.48-1.8=-1.32\ kg-m/s$

Final momentum $P_f=m\times v_f$

$P_f=0.06\times 8$

$P_f=0.48\ kg-m/s$

Impulse on the ball $=F_{avg}\Delta t$

Impulse $=1.5\times 10^3\times 1.2\times 10^{-3}=1.8\ N-s$

Initial velocity is given by

$u=\frac{P_i}{m}=\frac{-1.32}{0.06}$

$u=-22\ m/s$

i.e. initially ball is moving towards -x-axis

8 0

3 years ago

A rock dropped into a pond produces a wave that takes 11.3 s to reach the opposite shore, 26.5 m away. the distance between cons

Kay [80]

The wave takes 11.3 s to cover a distance of 26.5 m, so its speed is:
$v= \frac{S}{t}= \frac{26.5 m}{11.3 s}=2.35 m/s$

The distance between two consecutive crests is 3 m, and this corresponds to the wavelength of the wave. To find its frequency, we can use the relationship between the speed v, the wavelength $\lambda$ and the frequency f:
$f= \frac{v}{\lambda}= \frac{2.35 m/s}{3 m}=0.78 Hz$

6 0

3 years ago

What is the uncertainty of the position of the bacterium? express your answer with the appropriate units?

lbvjy [14]

For two un-related quantities, the Heisenberg uncertainty equations holds: the prduct of the two uncertainty quantities is greater than $\hbar/2$
Example of unrelated quantities are position and momentum, energy and time.
Thus
$\Delta x*\Delta p \ \textgreater \ \hbar/2$
Knowing the speed of the bacteria the uncertainty in its position is
$\Delta x \ \textgreater \ \hbar/(2 \Delta p) =\hbar/(2mv)$

4 0

2 years ago

Select the correct answer.

chubhunter [2.5K]

I believe it’s self-referent encoding

3 0

2 years ago

When a crown of mass 14.7 kg is submerged in water, an accurate scale reads only 13.4 kg. What material is the crown made of?

Bogdan [553]

Answer:

ρ = 1.13 10⁴ km/m³

Explanation:

For this exercise we use Newton's equilibrium equation

B –W + W_scale = 0

Where B is the thrust and W_scale is the balance reading

The push is given by Archimedes' law

B = ρ_water g V

B = W- W_scale

B = m g - m_scale g

Let's calculate

B = 14.7 9.8 - 13.4 9.8

B = 12.74 N

ρ_water g V = 12.74

V = 12.74 / ρ_water g

V = 12.74 / 1000 9.8

V = 0.0013 m³

Let's use density

ρ = m / V

We replace

ρ = 14.7 / 0.0013

ρ = 1.13 10⁴ km/m³

3 0

3 years ago