20.C. a. The "magnitude" of a vector is its size. Every magnitude is always positive: yes, or no? b. Given the coordinate system seen to the right, increasing numbers are upward and decreasing numbers are downward, Any vector with a negative value must point up or down? If a vector is a positive number, then which way does it point (up or down)? X = c. A student is doing a free fall problem and finds that a = -9.8 m/s², 5m, v = 3 m/s. If you think of the origin O as the earth's Then draw the three vectors: position, velocity and acceleration on The axis to the right. surface L-8 6- 10

3. Penny drops a leaf into the water which runs east downstream. She measures the distance the leaf travels as 3.0 meters in 9.0 seconds. Penny then swims across the river, orienting herself perpendicular to the water, and lets the river current carry her downstream. She swims across the 57 m wide river in 47 seconds. a. Sketch the overall vectors of the velocities of the person to the water, the water to the ground and the person to the ground. Write the equation for the velocity of the person relative to the ground with the appropriate subscripts b. Determine the velocity of the water in the river relative to the ground. c. How far downstream will Olaf drift?" d. Determine the velocity of the person relative to the water (with direction) e. Determine the velocity of the person relative to the ground (with direction).

Estimate the thickness of the Earth's atmosphere. From your chemistry class, you know that the most common speed of a nitrogen molecule is 700 m/s. The molecules' velocity is pointed along random directions, but some molecules head straight up; i.e. directly away from the Earth's center. Consider the thickness of the atmosphere as the highest point that such a nitrogen molecule can fly to, if it goes straight up. What is the altitude? m

A throws the ball with an initial velocity V0 = 90 km / hr at an angle α with the horizontal. If the ball goes through B, Determine a) the angle α and b) the angle θ that the vector VB makes with the horizontal.

An object is moving counter-clockwise in uniform circular motion at a constant speed of 3 m/s in a circle of radius 1.2 m. The magnitude of radial acceleration is 7.5 m/s?. Point A is at an angle of 15 degrees from the x axis. Sketching the position, velocity, and acceleration vectors may be helpful. A. Calculate the x and y components of the position vector for point A. B. Calculate the x and y components of the velocity vector for point A. C. Calculate the x and y components of the acceleration vector for point A. +y A +x 15° (0,0)

1. E

You decide to walk from your home to your friend's house. He lives 164 meters away from you at an angle 59° South of East. What is the eastern component of your displacement? m What is the southern component of your displacement? m