Physics Unit 3 - Projectile Motion

At the instant a ball is thrown horizontally over a level range, a ball held at the side of the first is released and drops to the ground. If air resistance is neglected, which ball strikes the ground first? Defend your answer.

They should hit the ground at the same time because they have the same amount of gravity and the same amount of time

Compare the time it takes for the cart to travel from X to Z, as compared to the time it takes the ball to fall from X to Y

They time to fall for both is the same

projectile

any object that moves through the air or space, acted on only by gravity (and air resistance, if any)

examples of projectiles

cannonball shot from a cannon, stone thrown into the air, ball rolling off the edge of a table, spacecraft circling

A ball launched into the air at 45° to the horizontal initially has

equal horizontal and vertical components

nonlinear motion

motion along a curved path

At the instant a horizontally pointed cannon is fired, a cannonball held at the cannon's side is released and drops to the ground. Which cannonball strikes the ground first, the one fired from the cannon or the one dropped?

neither - they both hit the ground at the same time because they have the same amount of gravity and the same amount of time

the ball moves the same horizontal distance in the equal time intervals because....

no horizontal component of force is acting on it

the path traced by a projectile accelerating in the vertical direction while moving at constant horizontal velocity is a...

parabola

when air resistance is small enough to neglect, the curved paths are

parabolic

resolution

the process of determining the components of a vector

components

two vectors at right angles that add up to a given vector

Most important, the horizontal component of motion for a projectile is completely independent of the

vertical component of motion

Terry and Angela look from their balcony to a swimming pool below that is 15 m from the bottom of their building. They estimate the balcony is 45 m high and wonder how fast they would have to jump horizontally to succeed in reaching the pool. What is your answer?

5 m/s

An ultra-light aircraft traveling north at 40 km/h in a 30-km/h crosswind (at right angles) has a ground speed of

50 km/h

A bird flies at a speed of 10 m/s in still air. If he flies into a 2 m/s headwind, how fast will he be traveling relative to the ground below?

8 m/s

On a bowling alley, Isabella rolls a bowling ball that covers a distance of 10 m in one second. The speed of the ball is 10 m/s. If the ball were instead dropped from rest off the edge of the building, what would be it's speed at the end of one second?

9.8 m/s

A cannon ball launched with an initial velocity of 141 m/s at an angle of 45° follows a parabola path and hits a balloon at the top of its trajectory. Neglecting air resistance, what is the acceleration of the cannon ball just before it hits the balloon?

9.8 m/s/s

If a 14 m/s vector makes an angle of 45° with the horizontal what are its horizontal and vertical components?

9.9 m/s

A cannon ball launched with an initial velocity of 141 m/s at an angle of 45° follows a parabola path and hits a balloon at the top of its trajectory. Neglecting air resistance, how fast is it going when it hits the balloon?

99.7 m/s

When air resistance acts on a projectile, does it affect horizontal component of velocity, the vertical component of velocity, or both? Defend your answer?

Both because air is on the x and the y axis.

If the cart's velocity were doubled, what would happen to the time the cart falls as compared to the time the ball falls?

The cart and ball will still land at the same time.

What happens to the velocity of the cart through its flight?

The horizontal component of the velocity remains constant while the vertical component increases as gravity acts on the cart

How is the horizontal component of velocity for a projectile affected by the vertical component?

The vertical component acts perpendicular to the horizontal and they are independent of each other.

Calculate Hotshot Harry's hang time if he moves horizontally 3 m during a 1.25 m high jump

1.0 s

Billie Joe stands on the Tallahatchie Bridge kicking stones into the water below. If Billie Joe kicks a stone with a horizontal velocity of 3.50 m/s, and it lands in the water a horizontal distance of 5.40 m from where Billie Joe is standing, what is the height of the bridge?(3sf)

11.7 m

A bird flies at a speed of 10 m/s in still air. Suppose that he encounters a 10m/s cross wind (at a right angle). What is his speed relative to the ground below?

14 m/s

Calculate the magnitude of the resultant of a pair of 100 km/h velocity vectors that are right angles to each other. (round to 3 s.f.)

141 km/h

Harry accidentally falls out of a helicopter that is traveling at 15 m/s. He plunges into a swimming pool two seconds later. What are the horizontal and vertical components of Harrys velocity just as he hits the water?

15 m/s, 20. m/s

Calculate the resultant velocity of an airplane that normally flies at 200 km/h if it encounters a 50 km/h headwind

150 km/h

Calculate the resulting speed of 120 km/h pointing due north when it encounters a wind of 90 km/h directed from the west. (round to 3 s.f.)

150 km/h

Robbie Knievel successfully jumped 69.5 m over a grand canyon gorge. Assuming that he started and landed at the same level and was airborne for 3.66 seconds, what height from the starting pointed did this daredevil achieve?

16.4 m

Burt is standing on a ladder picking apples in his grandfather's orchard. As he pulls each apple off the tree, he tosses it into a basket that sits on the ground 3.0 m meters below had a horizontal distance of 2.0 m from Burt. How fast must Burt throw the apples (horizontally) in order for them to land in the basket?(2sf)

2.6 m/s

Calculate the resultant velocity of an airplane that normally flies at 200 km/h if it encounters a 50 km/h tailwind

250 km/h

Emmanuel, the famous human cannonball of the Ringling Brothers Circus was fired out of a cannon with a speed of 24.0 m/s at an angle of 40.0° to the horizontal. If he landed in a net 56.6 m away at the same height from which he was fired, how long was Emmanuel in the air? (3 sf)

3.15 s

Harry accidentally falls out of a helicopter that is traveling at 15 m/s. He plunges into a swimming pool two seconds later. Assuming no air resistance, what was the horizontal distance between Harry and the swimming pool when he fell from the helicopter?

30. m

The movie "the gods must be crazy" begins with a pilot dropping a bottle out of an airplane. It is recovered by surprise native below, who thinks it is a message from the gods. If the plane from which the bottle was dropped was flying at an altitude of 500. m, and the bottle lands 400. m horizontally from the initial drop point, how fast was the plane flying when the bottle was released?(3sf)

39.6 m/s

In Moncton, New Brunswick, each high tide in the Bay of Fundy produces a large surge of water known as a tidal bore. If a riverbed fills with this flowing water that travels north with the speed of 1.0 m/s, what is the resulting velocity of a puffin who tries to swim east across the tidal bore with a speed of 4.0 m/s? (2sf) format answer: x m/s, y deg east of north

4.1 m/s, 76 deg east of north

At a meeting of physics teachers in Montana, the teachers were asked to calculate where a flour sack would land if droppped from a moving airplane. The plane would be moving horizontally at a constant speed of 60.0 m/s at an altitude of 300. m. If one of the physics teachers neglected air resistance while making his calculation, how far horizontally from the dropping point would he predict the landing? (3sf)

469 m