physics home work help

Question

Both car A and car B leave school when a stopwatch reads zero. car A travels at a constant 75 km/h, and a car B travels at a constant 85 km/h.

1. Draw a position-time graph showing the motion of both cars. How far are the two cars from school when the stopwatch reads 2.0 h? calculate the distances and show them on the graph.

2. Both cars passed a gas station 120 km from the school. When did each car pass station? calculate the times and ashow them on your graph?

Answer 1

Distance = velocity * time

Car A travels at a constant 75km/h

V_A  = 75km/h

V_B  = 85 km/h

Car B travels at a constant 85km/h

1)  When stop watch reads 2 hours

D_A = V_A *  T

D_A = 75 * 2

D_A  = 150 km

D_B = V_B *  T

D_B = 85 * 2

D_B  = 170 km

Car A distance in 2 hours is 150km

Car B distance in 2 hours is 170 km.

2) Both cars passed gas station 120km from the school.

D = 120km ,

V_A  = 75km/h

V_B  = 85 km/h

T_A = D/V_A

T_A = 120/75 = 1.6 hours

T_B = D/V_B

T_B = 120/ 85 = 1.4 hours

Car A pass station in 1.6 hours.

Car B pass station in 1.4 hours.

Graph

Obsrve the graph

Car A distance in 2 hours is 150km

Car B distance in 2 hours is 170 km.

Car A pass station in 1.6 hours.

Car B pass station in 1.4 hours.

Comments

Thank you