physics ch 1 and 2 hw and physics primer things to know
Starting position x=25m, undergoes displacement of x=-43m What is her final position?
26-43= -17m
A football is kicked straight up into the air; it hits the ground 4.6 ss later. What was the greatest height reached by the ball? Assume it is kicked from ground level.
4.6(1/2)=2.3 sec to go down v=(4.6s)(9.8m/s^2)/2= 22.54 m/a d=0(2.3)+1/2(9.8)(2.3^2)=26m
Luis is visiting a public garden that has a large, circular path. When he has walked one-quarter of the distance around the path, the magnitude of his displacement is 270 mm.
displacement= 270m use Pythagorean theorem: L^2=R^2 + R^2 270^2=2R^2 R=190.9m Diameter of path: D=2R D=2(190.9)=381.8m
Shannon decides to check the accuracy of her speedometer. She adjusts her speed to read exactly 70 mphmph on her speedometer and holds this steady, measuring the time between successive mile markers separated by exactly 1.00 mile.
distance traveled 1 mile 54sec=.0015hr 1mile/0.015hr= 67mp not accurate
takes 34s to walk frm x1=-10m to x2=-40 Calculate velocity
formula used: velocity: delta x / delta t to find delta x : xf-xi -40-(-10)= -30 -30m/34s=velocity= -.88 m/s
The sun is 27 ∘∘ above the horizon. It makes a 42 mm -long shadow of a tall tree.
h=21m
A hiker is climbing a steep 12 degree slope. Her pedometer shows that she has walked 1800 mmalong the slope. How much elevation has she gained? Express your answer with the appropriate units.
h=370m
converting 9.18 us to s 3.42km to meters 47cm/ms to m/s 60km/hr
multiply by 100000 = 9.18 x 10^-6 s 3.42x1000= 3420 meters 47x100= 4700m/s 60/3.6= 17m/s
Gretchen runs the first 4.0 kmkm of a race at 6.0 m/sm/s. Then a stiff wind comes up, so she runs the last 1.0 kmkm at only 4.0 m/sm/s.
t1=3,000m/6m/s=500s t2=1000m/4.0m/s=250s 750s 4000m/750s= 5.3m/s
A truck driver has a shipment of apples to deliver to a destination 440 miles away. The trip usually takes him 8.0 hours. Today he finds himself daydreaming and realizes 100 miles into his trip that that he is running 30 minutes later than his usual pace at this point. At what speed must he drive for the remainder of the trip to complete the trip in the usual amount of time?
v=440miles/8 hours= 55mph t=100/55=1.818 440-100=340/5.5=6.0mph
