In class activity
Key
Find the net force produced by a 30 N force and a 20 N force if they are acting in the same direction: Same direction forces add: 30 N + 20 N = 50 N Find the net force if the two forces are acting in opposite directions: Find difference for forces in opposite directions: 30 N – 20 N = 10 N Calculate the average speed of a tennis ball if it travels 24 m, the full length of the court, in 0.5s: Speed is distance
distance 24m m = = 48 time 0.5s s
Calculate the speed of a runner who travels 4 km in 30 minutes:
distance 4km km 4km 60 min km = = 0.133 or • =8 time 30 min min 30 min 1h h What is the acceleration of a ball rolling down a ramp, if it starts at rest, and gains the speed of 25 m/s in 5 s? Acceleration is change of velocity divided by a time interval so 25 m s =5m 5s s2
