All categories

3 years ago

A projectile is thrown at an angle 30° from horizontal. Which statement about its vertical component of velocity is true?

1 answer:

3 0

Answer: A
There is constant downward acceleration due to the gravitational force exerted on the object due to the earth's gravitational field
By Newton's second law,
Force=Acceleration * Mass

Since vertical velocity is upward while vertical acceleration is downward, vertical velocity decreases as it moves upward.

You might be interested in

a ball kicked with a velocity of 8m/s at an angle of 30 degree to horizontal. calculate the time of flight of the ball. (g=10ms^

posledela

Answer:

Approximately $0.8\; \rm s$ (assuming that air resistance is negligible.)

Explanation:

Let $v_0$ denote the initial velocity of this ball. Let $\theta$ denote the angle of elevation of that velocity.

The initial velocity of this ball could be decomposed into two parts:

Initial vertical velocity: $v_0(\text{vertical}) = v_0 \cdot \sin(\theta)$ .
Initial horizontal velocity: $v_0(\text{vertical}) = v_0 \cdot \cos(\theta)$ .

If air resistance on this ball is negligible, $v_0(\text{vertical})$ alone would be sufficient for finding the time of flight of this ball.

Calculate $v_0(\text{vertical})$ given that $v_0 = 8 \; \rm m \cdot s^{-1}$ and $\theta = 30^\circ$ :

$\begin{aligned}& v_0(\text{vertical}) \\ &= v_0 \cdot \sin(\theta) \\ &= \left(8 \; \rm m \cdot s^{-1} \right) \cdot \sin\left(30^{\circ}\right) \\ &= 4\;\rm m \cdot s^{-1} \end{aligned}$ .

Assume that air resistance on this ball is zero. Right before the ball hits the ground, the vertical velocity of this ball would be exactly the opposite of the value when the ball was launched.

Since $v_0(\text{vertical}) = 4\; \rm m \cdot s^{-1}$ , the vertical velocity of this ball right before landing would be $v_1(\text{vertical}) = -4\; \rm m \cdot s^{-1}$ .

Calculate the change to the vertical velocity of this ball:

$\begin{aligned}& \Delta v(\text{vertical}) \\ & = v_1(\text{vertical}) - v_0(\text{vertical}) \\ &= -8\; \rm m \cdot s^{-1}\end{aligned}$ .

In other words, the vertical velocity of this ball should have change by $8\; \rm m \cdot s^{-1}$ during the entire flight (from the launch to the landing.)

The question states that the gravitational field strength on this ball is $g = 10\; \rm m \cdot s^{-2}$ . In other words, the (vertical) downward gravitational pull on this ball could change the vertical velocity of the ball by $10\; \rm m\cdot s^{-1}$ each second. What fraction of a second would it take to change the vertical velocity of this ball by $8\; \rm m \cdot s^{-1}$ ?

$\begin{aligned}t &= \frac{\Delta v(\text{initial})}{g} \\ &= \frac{8\; \rm m \cdot s^{-1}}{10\; \rm m \cdot s^{-2}} = 0.8\; \rm s\end{aligned}$ .

In other words, it would take $0.8\; \rm s$ to change the velocity of this ball from the initial velocity at launch to the final velocity at landing. Therefore, the time of the flight of this ball would be $0.8\; \rm s\!$ .

5 0

3 years ago

Questions 1

Aleonysh [2.5K]

Answer:

Radiant to Chemical

Explanation:

I think

8 0

2 years ago

Read 2 more answers

The amplitude of a sound wave determines its

Savatey [412]

The Loudness i believe.

5 0

3 years ago

Read 2 more answers

A building superintendent twirls a set of keys in a circle at the end of a cord. If the keys have a centripetal acceleration of

maria [59]

Answer:

5.75m/s

Explanation:

The formula we need to use here is the formula of centripetal acceleration given as

$a=v^{2} /r$

we have the acceleration and the radius (luckly in the units we need them to be)

replacing it would yield

$114m/s^{2} =v^{2} /0.29m$

then solving for v

$\sqrt{114m/s^{2} * 0.29m }= v$

$\sqrt{33 m^{2} / s^{2}}= v\\ 5.75 m/s = v$

(notice how m/ $s^{2}$ * m yields $m^{2}/s^{2}$ which when applying the square root yield m/s)

8 0

3 years ago

The element that can act like a metal when it is under tremendous pressure and is probably responsible for Jupiter and Saturn's

STALIN [3.7K]

Answer:

Hydrogen is that element that can act like a metal when it is under tremendous pressure and is probably responsible for Jupiter and Saturn's magnetism as it is abundantly found on these Jovian planets.

Explanation:

5 0

3 years ago