Vector and Scalar Quantities
A vector is a quantity that has
magnitude and direction
The horizontal component of a projectile's velocity is independent of
the vertical component of its velocity
A connonball is launched from the ground at an angle of 30 degrees above the horizontal and a horizontal speed of 20 m/s. Ideally (no air resistance) the ball will land on the ground with a horizontal speed of
20 m/s
What is the resulant of a 4 unit vector and 3 unit vector at right angles to each other
5 units
T or F: A vector sum is called the resultant
True
A scalar is a quantity that has
magnitude
A ball thrown into the air at some angle. At the very top of the ball's path, it vertical velocity is
zero
A projectile launched horizontally hits the ground in 0.5 seconds. If it had been launched with a much higher speed in the same direction, it would have hit the ground (neglecting the earth's curvature and air resistance) in
0.5 s
Why do projectiles have a curved path?
Both an initial horizontal velocity and vertical velocity due to gravity
T or F: The length of a vector reprents its magnitude.
True
Velocity is a (vector or scalar) quantity
vector
At what part of a path does a projectile have minimum speed
at the top of its path
An object is fired horizontally in a vacuum. The projectile maintains its horizontal component of speed because it
is not acted on by any horizontal forces
After a rock that is thrown straight up reaches the top of its path and is starting to fall back down, its acceleration is (neglecting air resistance)
the same
At the instant a ball is thrown horizontally with a large force, an identical ball is dropped from the same height. Which ball hits the ground first (consider ideal situation, no air resistance)
Neither, they both hit the ground at the same time
If a vector that is 1 cm long represents a velocity of 10 km/h, what is the velocity of 2 cm long drawn to the same scale represent
20 km/h
If an object is thrown horizontally at 20 m/s, what is its Vx 3 seconds later?
20 m/s
If it an object is thrown upward, its acceleration would be
1 g downward
The approximate resultant of a pair of 10 unit vectors is
14 units
A boat is rowed at 8 km/h directly across a river that flows at 6 km/h. What is the resultant speed of the boat
10 km/h
Calculate the magnitude of a vector that is 10 units long and 50 units tall
about 51 units
What is the ideal angle for both the maximum distance and height.
45 degrees
If a flying snake horizontally leaps off a 250 m cliff and lands 100 m away from the cliff. What is its initial horizontal velocity?
about 14 m/s
A cannon with a barrel velocity of 100 m/s launches a cannonball horizontally from a tower. Neglecting air resistance, where will the cannonball be 5 second later
500 m
A boy on a 20 m tower throws a ball a distance of 60 m. At what speed, in m/s, is the ball thrown