1A. VAB = VA-VB = 75-85 = -10 km/hr
1B. VAC = VA-VC = 75-90 = -15 km/hr
1C. VBA = VB-VA = 85-75 = +10 km/hr
1D. VBC = VB-VC = 85-90 = -5 km/hr
1E. VCA = VC-VA = 90-75 = + 15 km/hr
1F. VCB = VC-VB = 90-85 = +5 km/hr
1G. VAT = VA-VT =75-(-100) = 175 km/hr
1H. VBT = VB-VT = 85-(-100) = 185 km/hr
1I. VCT = VC-VT = 90-(-100) = 190 km/hr
2. VTG = + 50 km/hr (train relative to ground)
VFT = -10 km/hr (fly relative to train)
A. VFT is information given in the problem
VFT = -10 km/hr
B. VTF = -VFT so VFT = + 10 km/hr
C. VFG = VFT + VTG = 50 + (-10) = 40 km/hr
3. First: VWG = + 2 m/s & VBW = 0 m/s
Second: VWG = + 2 m/s & VBW = 5 m/s
A. First: VBG = VBW + VWG = 0 + 2 = 2 m/s
Second: VBG = VBW + VWG = 5 + 2 = 7 m/s
B. First: t = x/v
t = 25/2 = 12.5 s
Second: t = 25/7 = 3.57 s
Total: 12.5 + 3.57 = 16.07 s
4. VPG = -200 km/hr VMG = +350 km/hr
A. VPM = VPG + VGM = -200 + (-350)= -550 km/hr
B. VMP = -VPM VMP = -(-550) = 550 km/hr
C. VMG is given in the problem as + 350 km/hr
Boxcar #1 B- Ball, T- Train, G- Ground
P- Person in other train
1. VBT = = 20 km/hr
2. VBG = VBT + VTG = 20 + 50 = 70 km/hr
3. VBP = VBG + VGP = 70 + (-80) = -10 km/hr
or VBP = VBG -VPG = 70 – 80 = -10 km/hr
4. VBP = VBG + VGP = 70 + (60) = 130 km/hr
or VBP = VBG -VPG = 70 – (-60) = 130 km/hr
5. VBP = VBG + VGP = 70 + (-50) = 20 km/hr
or VBP = VBG -VPG = 70 – 50 = 20 km/hr