In which situation is the acceleration of the car negative?
a) the velocity of a car was 75 km/h over 4 hours.
b) the velocity of a car reduced from 50 km/h to 35 km/h over one minute.
c) the velocity of a car increased from 40 km/h to 75 km/h over 15 minutes.
d) the velocity of a car was 45 km/h at 2: 00 pm and at 4: 00 pm the velocity of the car was 85 km/h.

1. most waves are caused by vibrations. what motion in a transmitting antenna causes the vibrations that produce radio waves? 2. name two common household appliances that produce electromagnetic waves other than radio waves. what kind of electromagnetic waves do they produce? 3. when you are in a car and it passes through a tunnel, the radio signal is sometimes lost. why do you think this happens?

An electron is traveling with initial kinetic energy k in a uniform electric field. the electron comes to rest momentarily after traveling a distance d. (a) what is the magnitude of the electric field

The illuminance of a surface varies inversely with the square of its distance from the light source. if the illuminance of a surface is 120 lumens per square meter when its distance from a certain light source is 6 meters, by how many meters should the distance of the surface from the source be increased to reduce its illuminance to 30 lumens per square meter?