A train is moving at a speed of 31 m/s toward a stationary observer at a train station. The train whistle blows with an actual frequency of 348 Hz. What horn frequency is heard by the engineer (riding on the train)?

Aparticle travels in a circular orbit of radius 21 m. its speed is changing at a rate of 23.1 m/s2 at an instant when its speed is 37.2 m/s. what is the magnitude of the acceleration (in m/s? ) of the particle?

Diego kicks a soccer ball from the end line. his fellow students time and mark the soccer ball as it moves down the field. the graph represents the ball's progress. based on the graph, during what time is the velocity constant and positive?

Aforce of 8,480 n is applied to a chart to accelerate it at a rate of 26.5 m/s2. what is the mass of the cart?