What is the efficient functioning of working memory increased by

A car accelerates uniformly from rest to 24.8 m/s in 7.88 s along a level stretch of road. Ignoring friction, determine the aver

nevsk [136]

Answer:

When he weight of the car is 8.55 x $10^{3}$ N then power = 314.012 KW

When he weight of the car is 1.10 x $10^{4}$ N then power = 43.76 KW

Explanation:

Given that

Initial velocity $V_{1}$ = 0

Final velocity $V_{2}$ = 24.8 $\frac{m}{s}$

Time = 7.88 sec

We know that power required to accelerate the car is given by

P = $\frac{change \ in \ kinetic \ energy}{time}$

Change in kinetic energy Δ K.E = $\frac{1}{2} m (V_{2}^{2} - V_{1}^{2} )$

Since Initial velocity $V_{1}$ = 0

⇒ Δ K.E = $\frac{1}{2} m V_{2} ^{2}$

⇒ Power P = $\frac{1}{2} \frac{m}{t} V_{2} ^{2}$

⇒ Power P = $\frac{1}{2} \frac{W}{g\ t} V_{2} ^{2}$ -------- (1)

(a). The weight of the car is 8.55 x $10^{3}$ N = 8550 N

Put all the values in above formula

So power P = $\frac{1}{2} \frac{8550}{(9.81)\ (7.88)} (24.8) ^{2}$

P = 314.012 KW

(b). The weight of the car is 1.10 x $10^{4}$ N = 11000 N

Put all the values in equation (1) we get

P = $\frac{1}{2} \frac{11000}{(9.81)\ (7.88)} (24.8) ^{2}$

P = 43.76 KW

5 0

2 years ago

Astronomers are comparing two stars that are known to have the same luminosity. Star A is observed to be 4 times brighter than s

GaryK [48]

The answer is two3988140

7 0

2 years ago

You are standing on a skateboard, initially at rest. A friend throws a very heavy ball towards you. You can either catch the bal

harina [27]

To solve this problem we will apply the concept related to the moment, which describes the change in speed in proportion to the body mass. The momentum can be described under the general equation

$p = mv$

Where,

m = mass

v = Velocity

The change in momentum is the difference between the final moment and the initial moment

$\Delta p = p_f - p_i$

Where,

$p_f =$ Final momentum

$p_i =$ Initial momentum

After catching the ball, the ball comes to rest position and speed of the ball is zero.

$p_f = 0$

The change in momentum on catching the ball is

$\Delta p = 0 - mv$

$\Delta p = -mv$

The momentum during the catching of the ball is

$p_i = mv$

Now during deflection of the ball, we know that there is an initial momentum and a negative final momentum because it moves with the same speed but in the opposite direction, that is

$p_f = -mv$

The momentum is negative since during deflection the ball moves with same speed in opposite direction

$\Delta p = -mv-mv$

$\Delta p = 2-mv$

Therefore, the correct ansswer is B: catch the ball in order to minimize your speed on the skateboard

7 0

2 years ago

An experiment is designed to test the relationship between the initial height of a basketball before it is dropped to the height

Virty [35]

Answer:

A. The starting height of the ball

Explanation:

When we talk about controlled variables, we refer to the variable that should be kept the same throughout the experiment. The reason why we do this, is to limit anything else that is not being tested, that may affect the results of the experiment.

In the scenario given, the experiment is to see the relationship between the <u>initial height of a basketball</u> and the <u>height of its rebound bounce. </u>

So you the starting height of the ball should vary, meaning it is NOT controlled.

3 0

2 years ago

3.00 m3 of a fixed mass of a gas at 150 kPa. Calculate the pressure if the volume is reduced to 1.20 m3 at a constant temperatur

viktelen [127]

Answer:

P₂ = 375 kPa.

Explanation:

Given that,

Initial volume, V₁ = 3 m³

Initial pressure, P₁ = 150 kPa

Final volume, V₂ = 1.2 m³

We need to find the final pressure.

At constant temperature,

$P\propto \dfrac{1}{V}\\\\P_1V_1=P_2V_2\\\\P_2=\dfrac{P_1V_1}{V_2}\\\\P_2=\dfrac{150\ kPa\times 3\ m^3}{1.2\ m^3}\\\\P_2=375\ kPa$

So, the new pressure is 375 kPa.

6 0

2 years ago