Physics Final

If you know the value of a and the angle Θ, what trigonometry function do you use to find the x component of a vector?

cosine

An object's acceleration at the top of its flight is zero.

false

In chapter 3 of your text, the equations we use treat air-resistance as negligible.

true

The one variable common to motion in both the x- and y-directions is time.

true

The x- and y- components of a velocity vector are always perpendicular.

true

A shell is shot into the air with an initial speed of 36.0 m/s at an angle of 24.0º above the horizontal. The fuse is timed to ignite the shell just as it reaches its highest point above the ground. Calculate the height at which the shell explodes?

10.9 meters

A soccer ball is kicked toward the goal, which is 15 𝑚 away across a level pitch. The initial velocity of the soccer ball is 19 𝑚/ 𝑠 at an angle of 43° above the horizontal. Assume ideal projectile motion. Determine the initial horizontal velocity of the ball.

13.9m/s

A ball is thrown in the air at an angle of 35.0° to the ground, with an initial speed of 42⁢m/s. How far from its original position does it land?

169 meters

A ball is thrown in the air at an angle of 40∘. If the maximum height reaches is 10m, what must be its initial speed?

21.8 m/s

You hit a ball horizontally from the top of a cliff that is 80m tall. The ball has an initial velocity of 10.0m/s. What is the horizontal range of the ball?

40.4 meters

Neglecting air resistance, what angle produces the maximum range and why?

45 degrees because it is half way between both x and y components, yielding optimal distribution of force on an object

A ball is thrown in the air with an initial velocity of 10.0m/s. If it reaches a maximum height of 3.0m, what angle would it have been thrown at?

50 degrees

What is the acceleration due to gravity on Earth?

9.8m/s^2

At what angle should you hold the bow to achieve maximum height?

90 degrees

A water balloon cannon is fired at 30m/s at an angle of 50∘ above the horizontal. How far away will it fall?

90.4 meters

Horizontal and vertical motions of a projectile are independent of each other. What is meant by this?

Any object in projectile motion falls at the same rate as an object in freefall, regardless of its horizontal velocity.

Where in an objects' motion that is a projectile, is the vertical velocity zero? Why?

At the apex of the objects height because its velocity has run out and it is changing direction due to gravity.

If a ball is rolled off a table and one dropped from the table at the same time, what happens?

Both hit the ground at the same time.

Assume the ground is uniformly level. If the horizontal component a projectile's velocity is doubled, but the vertical component is unchanged, what is the effect on the time of flight?

The time to reach the ground would remain the same since the vertical component is unchanged.

If a soccer ball full of air is dropped from the same height as one full of lead, what happens?

They both hit the ground at the same time.

The vectors to show an object's motion from one location to the next should be drawn?

head to tail

For an object going through projectile motion, does the horizontal trajectory change throughout the motion if wind resistance is disregarded?

no

Ignoring air resistance, the horizontal component of a projectile's velocity does what?

remains constant

Speed is a ______ quantity whereas velocity is a ______ quantity.

scalar, vector

If you know the value of a and the angle Θ, what trigonometry function do you use to find the y component of a vector?

sine

Range as defined in chapter 3 of our text is....

the horizontal distance traveled by a projectile

What is an example of a projectile that continually falls around the Earth?

the moon

The path of an object going through projectile motion is called ....

trajectory

All motion must be described as relative to something.

true

For an object that is going through projectile motion, the time it spends in the air depend on the ...

vertical motion