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4 years ago

Can someone help me?!!!!!

Physics

1 answer:

sammy [17]4 years ago

4 0

Answer:

Explanation:

The first one is false. A vector has a magnitude and a direction; a scalar only has a magnitude. The two cannot be added together.

The second one is false. The magnitude of a vector is found using Pythagorean theorem: c² = a² + b². The only way the magnitude of a vector (c) can be 0 is if both components are 0 (a=0 and b=0).

The third one is true. A vector in Quadrant III will have negative components but can still have a positive magnitude. For example, a vector with magnitude 1 and direction 225° has a positive magnitude and negative components.

The fourth one is false. Rotating a vector will change it.

The fifth one is false. A vector sum can only be 0 if the two vectors have equal magnitudes and opposite directions.

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The Problems: 1. Xavier starts at a position of 0 m and moves with an average speed of 0.50 m/s for 3.0 seconds. He normally mov

NemiM [27]

Answer:

(1). His final position is 1.5 m.

(2). The final position of the hedgehog is 3 m.

(3). The final position of the tortoise

(4). Her race time is 80 sec.

(5). It take to finish in 5 hr.

Explanation:

(1). Given that,

Initial position = 0 m

Average speed = 0.50 m/s

Time = 3.0 s

We need to calculate the final position

Using formula of average speed

$v_{av}=\dfrac{x_{f}+x_{i}}{t}$

Where, $x_{f}$ = final position

$x_{i}$ = Initial position

t = total time

Put the value into the formula

$0.50=\dfrac{x_{f}+0}{3.0}$

$x_{f}=0.50\times3.0$

$x_{f}=1.5\ m$

(2). Given that,

Initial position = 0 m

Average speed = 0.75 m/s

Time = 4.0 s

We need to calculate the final position

Using formula of average speed

$v_{av}=\dfrac{x_{f}+x_{i}}{t}$

Put the value into the formula

$0.75=\dfrac{x_{f}+0}{4.0}$

$x_{f}=0.75\times4.0$

$x_{f}=3\ m$

(3). Given that,

Average speed = 1.25 m/s

Time = 3.0 sec

Initial position = 1.0 m

We need to calculate the final position

Using formula of average speed

$v=\dfrac{x_{f}+x_{i}}{t}$

Put the value into the formula

$1.25=\dfrac{x_{f}+1.0}{3.0}$

$x_{f}=1.25\times3.0-1.0$

$x_{f}=2.75\ m$

(4). Given that,

Average speed = 1.25 m/s

Distance = 100 m

We need to calculate the time

Using formula of time

$t=\dfrac{d}{v}$

Put the value into the formula

$t=\dfrac{100}{1.25}$

$t=80 sec$

(5). Given that,

Average speed = 5 miles/hr

Suppose, distance = 25 miles

We need to calculate the time

Using formula of time

$t=\dfrac{d}{v}$

Put the value into the formula

$t=\dfrac{25}{5}$

$t=5\ hr$

Hence, (1). His final position is 1.5 m.

(2). The final position of the hedgehog is 3 m.

(3). The final position of the tortoise

(4). Her race time is 80 sec.

(5). It take to finish in 5 hr.

5 0

4 years ago

An object is thrown with a horizontal velocity of 20 m/s from a cliff that is 125 m above level ground. If air resistance is neg

Serjik [45]

Given that,

Horizontal velocity of the object, v = 20 m/s

Height of the cliff, h = 125 m

We need to find the time that it takes the object to fall to the ground from the cliff is most nearly. It can be calculated using second equation of motion. Let us consider that the initial speed of the object is 0. So,

$h=ut+\dfrac{1}{2}at^2$

Here, a = g and u = 0

$h=\dfrac{1}{2}at^2\\\\t=\sqrt{\dfrac{2h}{g}} \\\\t=\sqrt{\dfrac{2\times 125}{10}} \\\\t=5\ s$

So, the object will take 5 seconds to fall to the ground from the cliff.

5 0

3 years ago

1.The across each resistor is the same in a series circuit. ) voltage current

Ber [7]

Answer:

The answer is Current.

Explanation:

In a series circuit, every component will have the same current.

In parallel circuit, all voltage of component remains the same.

3 0

3 years ago

Read 2 more answers

An archer fish spies a meal of a grasshopper sitting on a long stalk of grass at the edge of the pond in which he is swimming. I

andrew-mc [135]

Answer:

The archerfish must spit at a minimum speed of $3.43m/s$ at an angle of $69.14\°$ above the horizontal.

Explanation:

First of all, we need to find the angle above the horizontal at which the archerfish must spit, as we can see in the attachment this angle is $\Theta = 69.14\°$ .

Then we use the formula $h=\frac{v_{0}^{2}sin^{2} \Theta}{2g}$ , as we clear it for $v_{0}$ , we obtain, $v_{0}=\frac{\sqrt{2gh} }{sin\Theta}=\frac{\sqrt{2(9.8m/s^{2})(0.525m)} }{sin(69.14\°)}=3.43m/s$ , therefore the archerfish must spit at a minimum speed of $3.43m/s$ at an angle of $69.14\°$ above the horizontal.