TRUE OR FALSE: The following drops were most likely dropped from a 90 degree angle.

A dockworker applies a constant horizontal force of 80.0 N to a block of ice on a smooth horizontal floor. The frictional force

Tamiku [17]

Answer:

(a) 91 kg (2 s.f.) (b) 22 m

Explanation:

Since it is stated that a constant horizontal force is applied to the block of ice, we know that the block of ice travels with a constant acceleration and but not with a constant velocity.

(a)

$s \ = \ ut \ + \ \displaystyle\frac{1}{2} at^{2} \\ \\ a \ = \ \displaystyle\frac{2(s \ - \ ut)}{t^{2}} \\ \\ a \ = \ \displaystyle\frac{2(11 \ - \ 0)}{5^{2}} \\ \\ a \ = \ \displaystyle\frac{22}{25} \\ \\ a \ = \ 0.88 \ \mathrm{m \ s^{-2}}$

Subsequently,

$F \ = \ ma \\ \\ m \ = \ \displaystyle\frac{F}{a} \\ \\ m \ = \ \displaystyle\frac{80 \ \mathrm{kg \ m \ s^{-2}}}{0.88 \ \mathrm{m \ s^{-2}}} \\ \\ m \ = \ 91 \mathrm{kg} \ \ \ \ \ \ (2 \ \mathrm{s.f.})$

*Note that the equations used above assume constant acceleration is being applied to the system. However, in the case of non-uniform motion, these equations will no longer be valid and in turn, calculus will be used to analyze such motions.

(b) To find the final velocity of the ice block at the end of the first 5 seconds,

$v \ = \ u \ + \ at \\ \\ v \ = \ 0 \ + \ (0.88 \mathrm{m \ s^{-2}})(5 \ \mathrm{s}) \\ \\ v \ = \ 4.4 \ \mathrm{m \ s^{-1}}$

According to Newton's First Law which states objects will remain at rest

or in uniform motion (moving at constant velocity) unless acted upon by

an external force. Hence, the block of ice by the end of the first 5

seconds, experiences no acceleration (a = 0) but travels with a constant

velocity of 4.4 $m \ s^{-1}$ .

$s \ = \ ut \ + \ \displaystyle\frac{1}{2}at^{2} \\ \\ s \ = \ (4.4 \ \mathrm{m \ s^{-2}})(5 \ \mathrm{s}) \ + \ \displaystyle\frac{1}{2}(0)(5^{2}) \\ \\ s \ = \ 22 \ \mathrm{m}$

Therefore, the ice block traveled 22 m in the next 5 seconds after the

worker stops pushing it.

4 0

2 years ago

Carbon monoxide (CO) _____.

bekas [8.4K]

A. It is a compound made of oxygen and carbon

3 0

3 years ago

Read 2 more answers

Calculate the standard electrode potential difference (e°) of the daniell cell (at 1 bar) if temperature is 473.15 k.

anzhelika [568]

Missing data in the text of the exercise: The molar concentration of Zinc is 10 times the molar concentration of copper.

Solution:

1) First of all, let's calculate the standard electrode potential difference at standard temperature. This is given by:
$E^0=E_{cat}^0-E_{an}^0$
where $E_{cat}^0$ is the standard potential at the cathode, while $E_{an}^0$ is the standard potential at the anode. For a Daniel Cell, at the cathode we have copper: $E_{Cu}^0=+0.34 V$ , while at the anode we have zinc: $E_{Zn}^0=-0.76 V$ . Therefore, at standard temperature the electrode potential difference of the Daniel Cell is
$E^0=+0.34 V-(-0.76 V)=+1.1 V$

2) To calculate $E^0$ at any temperature T, we should use Nerst equation:
$E^0(T)=E^0- \frac{R T}{z F} \ln \frac{[Zn]}{[Cu]}$
where
$R=8.31 J/(K mol)$
$T=473.15 K$ is the temperature in our problem
$z=2$ is the number of electrons transferred in the cell's reaction
$F=9.65\cdot 10^4 C/mol$ is the Faraday's constant
$[Zn]$ and $[Cu]$ are the molar concentrations of zinc and in copper, and in our problem we have $[Zn]=10[Cu]$ .
Using all these data inside the equation, and using $E^0=+1.1 V$ , in the end we find:
$E^0(T)=E^0- \frac{R T}{z F} \ln \frac{[Zn]}{[Cu]}=+1.053 V$

8 0

3 years ago

A ball is dropped from the top of the building.it initially moves at 4.0 m/s after 0.5 seconds it moves at 3.8m/s what force is

Ivahew [28]

The correct answer is

Air resistance

In fact, when a ball is in free fall, there are two forces acting on it:

- its weight (force of gravity), acting downward

- the air resistance, acting upward

The effect of the weight is to accelerate the ball, because its direction is the same as the direction of motion of the ball, while the effect of the air resistance is to slow down the ball, because its direction is opposite to that of the motion.

6 0

3 years ago

What two forces are balanced in what we call gravitational equilibrium? What two forces are balanced in what we call gravitation

JulijaS [17]

Question:

What two forces are balanced in what we call gravitational equilibrium?

A) the electromagnetic force and gravity

B) outward pressure and the strong force

C) outward pressure and inward gravity

D) the strong force and gravity

E) the strong force and kinetic energy

Answer:

The correct answer is C) Outward Pressure and Inward gravity

Explanation:

Gravitational equilibrium is a balance between the inward pull of gravity and the outward push of internal gas pressure. It also refers to the condition of a star in which the weight of overlying layers at each point is balanced by the total pressure at that point.

As the weight increases in the lower layers of the sun, the pressure also increases to maintain this balance. So you find that the outward push of pressure balances the inward pull of gravity thus creating an equilibrium.

Why is gravitational equilibrium important?

The simple answer is <u>balance. </u> If for instance the sun as a stable star (which has gravitational equilibrium) loses it's balance, it becomes highly unstable and prone to violent outbursts. These outbursts are caused by the very high radiation pressure at the star's upper layers, which blows significant portions of the matter at the "surface" into space during eruptions that may rage for several years. Of course such a condition is adverse to the existence and support of life.

Cheers!

6 0

3 years ago