Part A. a stone is thrown horizontally with and initial speed of 20 m/s from the
ID: 1331922 • Letter: P
Question
Part A. a stone is thrown horizontally with and initial speed of 20 m/s from the edge of a cliff. A stopwatch measures the stones trajectory time from the top of the cliff to the bottom to be 4.0s. What is the height of the cliff if air resistance is negligibly small? A. 64m B. 78m C.84m D.46m Part B A car of mass 1400 kg that is traveling at 24m/s starts to slow down and comes to a complete stop in 400m. What is the magnitude of the average braking force acting on the car? A.688n B.1008n C. 1238n D.968n Part A. a stone is thrown horizontally with and initial speed of 20 m/s from the edge of a cliff. A stopwatch measures the stones trajectory time from the top of the cliff to the bottom to be 4.0s. What is the height of the cliff if air resistance is negligibly small? A. 64m B. 78m C.84m D.46m Part B A car of mass 1400 kg that is traveling at 24m/s starts to slow down and comes to a complete stop in 400m. What is the magnitude of the average braking force acting on the car? A.688n B.1008n C. 1238n D.968n Part A. a stone is thrown horizontally with and initial speed of 20 m/s from the edge of a cliff. A stopwatch measures the stones trajectory time from the top of the cliff to the bottom to be 4.0s. What is the height of the cliff if air resistance is negligibly small? A. 64m B. 78m C.84m D.46m Part B A car of mass 1400 kg that is traveling at 24m/s starts to slow down and comes to a complete stop in 400m. What is the magnitude of the average braking force acting on the car? A.688n B.1008n C. 1238n D.968nExplanation / Answer
Part A)
Given Vix=20m/s, Viy=0m/s
Use below kinematic equation vertically
h=Viy*t-1/2*g*t^2
h=0*t-1/2*9.8*4^2 = -78.4m
Hence correct answer: B. 78m
Part B)
Let’s first calculate acceleration, a
Use equation,
Vf^2=Vi^2+2*a*d
0^2=24^2+2*a*400 => a= -0.72m/s^2
F=m*a = 1400*-0.72 = - 1008 N
Hence correct answer: B. 1008n