The sound takes 0.2 seconds to go to the hill and come back, so it would take 0.1 seconds to get to the hill. then v=d/t; v=33.2/0.1
v=332m/s
Answer:
The total amount of energy, kinetic plus potential, remains the same.
Explanation:
A 2000-kg car decelerated from 10 m/s to 5 m/s. What is the work done on the car ?
Known :
Car’s mass (m) = 2000 kg
Initial speed (vo) = 10 m/s
Final speed (vt) = 5 m/s
Wanted: net work
Solution :
Net work :
Wnet= ΔEK
Wnet = ½ m (vt2 – vo2)
Wnet = ½ (2000)(52 – 102)
Wnet = (1000)(25 – 100)
Wnet = (1000)(-75)
Wnet = -75,000 Joule
The minus sign indicates that the direction of displacement is opposite with the direction of the net force.
Straight line distance between their home and the store can be solve using cosine law. first is solve the angle which is180 - 45 = 135 degree
C^2 = a^2 + b^2 - 2ab cos(135)c^2 = 5^2 + 5^2 - 2(5)(5) cos(135)c^2 = 85.35c = 9.24 km is the straight line distance between their home and the store