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2 years ago

In describing a vector, what must you describe besides the magnitude?

Physics

1 answer:

Anton [14]2 years ago

7 0

Answer:

Direction

Explanation:

A vector is a geometrical representation of physical quantity. It has a particular direction with a specific magnitude.

In the geometry of space whether it is two dimensional or three dimensional the vector quantity has a specific direction. Such as a stone is thrown with a velocity in a particular direction.

The path of the stone in three-dimension shows its direction and speed is its magnitude.

Hence, the velocity of stone has two property magnitude mentioned as speed and particular direction.

On writing the mathematical expressions for vectors, it is denoted by arrow mark on its top as shown below.

$\vec{A}$

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An object starts at Xi = -4m with an initial velocity of 4m/s. It experiences an acceleration of -2 m/s^2 for 2 seconds, followe

GalinKa [24]

Answer:

a) 0 m/s

b) - 24 m/s

c) - 68 m

Explanation:

Given:

Initial distance = - 4 m

Initial velocity, u = 4 m/s

1) acceleration, a = - 2 m/s² for time, t = 2 seconds

thus,

velocity after 2 seconds will be

from Newton's equation of motion

v = u + at

v = 4 + (-2) × 2

v = 0 m/s

2) Velocity after 2 second is the initial velocity for this case

given acceleration = - 6 m/s² for 4 seconds

thus,

final velocity, v = 0 + ( - 6 ) × 4 = - 24 m/s

here the negative sign depicts the velocity in opposite direction to the initial direction of motion

thus, velocity after 6 seconds = - 24 m/s

3) Now,

Total displacement in 6 seconds

= Displacement in 2 seconds + Displacement in 4 seconds

From Newton's equation of motion

$s=ut+\frac{1}{2}at^2$

where,

s is the distance

u is the initial speed

a is the acceleration

t is the time

thus,

= $0\times2+\frac{1}{2}\times(-2)\times2^2$ + $0\times4+\frac{1}{2}\times-6\times4^2$

= - 16 - 48

= - 64 m

Hence, the final displacement = - 64 - 4 = - 68 m

5 0

2 years ago

A car is stopped for a traffic signal. When the light turns green, the car accelerates, increasing its speed from zero to 5.27 m

jeyben [28]

Answer:

See explanation

Explanation:

From Newton's law; the rate of change of momentum is proportional to the impressed force. Hence;

F.t = mv- mu

F= force

t= time

m= mass

V= final velocity

u = initial velocity

since u = 0, mv= 0

F= MV/t

F= 69.8 × 5.27/0.833

F= 442 N

Impulse = Ft= 442 × 0.833= 368 Ns

5 0

2 years ago

Standing on the roof of a (42.0+A) m tall building, you throw a ball straight up with an initial speed of (14.5+B) m/s. If the b

RSB [31]

First, we must find the vertical distance traveled upwards by the ball due to the throw. For this, we will use the formula:

2as = v² - u²

Because the final velocity v is 0 in such cases

s = -u²/2a; because both u and a are downwards, the negative sign cancels

s = 14.5² / 2*9.81
s = 10.72 meters

Next, to find the time taken to reach the ground, we need the height above the ground. This is:
45 + 10.72 = 55.72 m

We will use the formula
s = ut + 0.5at²

to find the time taken with the initial velocity u = 0.

55.72 = 0.5 * 9.81 * t²

t = 3.37 seconds

4 0

3 years ago

Find the equivalent resistance Req between terminals a and b if terminals c and d are open and again if terminals c and d are sh

adoni [48]

Answer:

351 ohm

720 ohm

Explanation:

When c and d are open:

Terminals c and d are open.. If you redraw the circuit as below, you can see that the two resistors in the first column are in parallel as, they are connected together at both pairs of terminals (due to the short).

Hence, we have a pair of parallel resistors:

Req1 = (R1*R2)/ (R1 + R2) = 360*540/(360+540) = 216 ohms

Req2 = (R3*R4)/ (R3 + R4) = 180*540/(180+540) = 135 ohms

Now these two sets are in series with another Hence,

Req = Req1 + Req2 = 216 + 135 = 351 ohms

Answer: 351 ohms

When c and d are shorted:

The current will flow through the least resistant path naturally from resistors R3 and R1 or R4.

Both of these resistor lie in a single path placing the resistors in series to one another, hence

Req = R3 + R1 = 180 + 540 = 720 ohms

Answer:720 ohms

7 0

2 years ago

Car A hits car B (initially at rest and of equal mass) from behind while going 15 m/s Immediately after the collision, car B mov

Mamont248 [21]

Given :

Initial speed of car A is 15 m/s and initial speed of car B is zero.

Final speed of car A is zero and final speed of car B is 10 m/s.

To Find :

What fraction of the initial kinetic energy is lost in the collision.

Solution :

Initial kinetic energy is :

$K.E_i = \dfrac{15^2m}{2} + 0\\\\K.E_i = \dfrac{225 m}{2}$

Final kinetic energy is :

$K.E_f = \dfrac{10^2m}{2} + 0\\\\K.E_f = \dfrac{100m}{2}$

Now, fraction of initial kinetic energy loss is :

$Loss = \dfrac{\dfrac{225m}{2}-\dfrac{100m}{2}}{\dfrac{100m}{2}}\\\\Loss = \dfrac{125}{100}\\\\Loss = 1.25$

Therefore, fraction of initial kinetic energy loss in the collision is 1.25 .

6 0

2 years ago