7.C. a. When you add two vectors you get another vector: yes or no? b. When you subtract two vectors you get another vector: yes or no? c. Given the coordinate system below where increasing numbers are to the right and decreasing numbers are to the left, any vector component that has a negative value must point left or right? H H H -10 -9 -8 -7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 7 8 9 10 d. If a vector has a positive component, then which way does it point for the axis above? e. The magnitude of a vector means its size. Size is always a positive number. The magnitude of any one-dimensional vector can be found by taking its absolute value: yes, or no? ANS: yes. f. What is the quick name given to "the magnitude of the velocity vector". HELP: it starts with the letter s. 8.6. a. Draw the addition of the two force vectors on a separate sheet: this is called the net force or total force Fnet = F+ F2. HELP: Use the tail-to-tip drawing rule F b. Suppose has size 6 and 72 has size 2. What is the size of Fnet? HELP: recall that the size of a vector is called its magnitude and is always a positive quantity. c. Two momentum vectors are seen below. Draw Pnet = P1 + P2 on a separate sheet 12 P2 d. Suppose p has size 8 and 12 has size 4. What is the size (positive) of Pnet? 9.6. a. Two position vectors are seen. Draw the displacement 2 - on a separate sheet. HELP: Use the tip-to-tip drawing rule x2 b. Suppose has magnitude 6 and x2 has magnitude 2. - What is the magnitude of Ax = x2 4 19 Dashboard 900 000 Calendar To Do Notifications Inbox 3:02 AM Sat Mar 9 Back 7 2ag HCHW Ch 2 (31).pdf c. Two velocity vectors are seen. Draw the difference 12 - 11. Suppose has magnitude 5 and 2 has magnitude 10. What is the magnitude of Av? 2 1 ^ C 80% 10.8. a. A car moves one-dimensionally. It starts at x = 15m then moves a distance of 200m to the right, then 100m left. Find the total distance moved and displacement of the car for the entire motion. As part of your work draw the path of the car and the following vectors: initial position, final position and displacement. ANS: 300, 100 b. A second car starts at -20m and drives 50m to the right in 4s then moves 80m left in 6s. Find its initial and final position, net displacement, total distance moved, average speed and average velocity. Indicate which are scalars(S) and which are vectors(V). Draw the object at the initial and final positions (ok to draw the car as a box0 and draw all vectors involved on the axis below. -40 -30 -20 -10 10 20 30 40 11.C. Displacement Ax is often interpreted as a "directed distance". Explain what the difference is between "distance" and "directed distance". As a feel for what this question is asking, consider the two situations below for the initial and final positions of a moving object. #1. X1 = 3m, x2 = 7m #2. x = 7m, x2 = 3m 12.C. S (a). Car #1 has position x = -40m and velocity v = 3. Car #2 has position x = 10m with velocity v = -9 Draw the cars and the associated vectors below. m S T T meter -40 -30 -20 -10 10 20 30 40 50 19 Dashboard Calendar 000 To Do Notifications Inbox 3:02 AM Sat Mar 9 Back 7 2ag HCHW Ch 2 (31).pdf (b). How much longer should car #2's velocity be drawn compared to car #1? (c). Explain why you can't compare a position vector's size to a velocity vector's size. 13.C. Suppose remote-control toy car can move backward/forwards according to the equation x = 2t3 5t2 where position is in [m] and time in [s] - a. True or false: the t variable in this equation is an "instant" of time and can be any real number like 0, 0.3s, 2s, 3.86s, or 11.774s. b. Compute the car's average velocity from Os to 3s HELP: Vavg = At 14.E. Average velocity is always computed between two instants in time (called a time interval) whereas instantaneous velocity is always computed at one instant in time. We explore how these two (average versus instantaneous) are related below. Instantaneous velocity v: how is it different than average velocity Vavg 1. Average velocity Vavg is always computed between two times t, t 2. Instantaneous velocity v is the velocity at one instant in time t and is approximately equal to the average velocity if the time interval At = t2- t is small. v(t) = Vavg when t is close to t approximately equal to In a physics experiment a toy car moves with position function x(t) = 0.15t function notation Fill out the two tables below (the first row is done for you already) time [s] position [m] 5 18.75 2 1.5 1.1 1.01 1 Vavg from 1s to 5s 4.65 m/s Vavg from 1s to 2s Vavg from 1s to 1.5s Vavg from 1s to 1.1s Vavg from 1s to 1.01s What is the best approximation to the car's instantaneous velocity at 1s? ANS: 0.45 5 19 Dashboard Calendar 000 To Do Notifications Inbox ^ C 80%