(a) A light-rail commuter train accelerates at a rate of 1.35 m/s 2 . How long does it take to reach its top speed of 80.0 km/h, starting from rest? (b) The same train ordinarily decelerates at a rate of 1.65 m/s 2 . How long does it take to came to a stop from its top speed? (c) In emergencies, the train can decelerate more rapidly, coming to rest from 80.0 km/h in 8.30 s. What is its emergency acceleration in meters per second sqquared?
(a) A light-rail commuter train accelerates at a rate of 1.35 m/s 2 . How long does it take to reach its top speed of 80.0 km/h, starting from rest? (b) The same train ordinarily decelerates at a rate of 1.65 m/s 2 . How long does it take to came to a stop from its top speed? (c) In emergencies, the train can decelerate more rapidly, coming to rest from 80.0 km/h in 8.30 s. What is its emergency acceleration in meters per second sqquared?
(a) A light-rail commuter train accelerates at a rate of
1.35
m/s
2
. How long does it take to reach its top speed of 80.0 km/h, starting from rest? (b) The same train ordinarily decelerates at a rate of
1.65
m/s
2
. How long does it take to came to a stop from its top speed? (c) In emergencies, the train can decelerate more rapidly, coming to rest from 80.0 km/h in 8.30 s. What is its emergency acceleration in meters per second sqquared?
A) A subway train starts from rest at a station and accelerates at a
rate of 16.5 m/s? for 13.1 s. It runs at constant speed for 69.7s and
slows down at a rate of 3.45 m/s? until it stops at the next station.
What is the total distance covered?
B) A plane flies from London Heathrow Airport to Dubai
International Airport, a distance of approximately 5500 km at an
average speed of 1200 km/h. The return trip was made at an
average speed of 1050 km/h. Find the average speed for the whole
journey.
From rest, the cheetah can accelerate at 8.8 m/s2 and reach a top speed of 30 m/s (108 km/h)! It can maintain this maximum speed over a distance of about 400 meters before it needs to stop.On the other hand, the Thomson’s gazelle has a top speed of 70 km/h, which is less than the cheetah’s, but it can maintain this top speed for a while as well. From rest, the gazelle can accelerate at 4.5 m/s2 to reach its top speed.
When a cheetah goes after a gazelle, success or failure is a simple matter of kinematics: you will determine if the cheetah’s high speed is enough to allow it to reach its prey before it runs out of steam (or time).You will apply basic kinematics and simple assumptions to determine how a chase can play out.
Q2. In the elapsed time that the cheetah started and must stop, what distance can the gazelle cover?
(again clearly show your calculations)
Why is the 70 multiplied by 5/18?
A car sits on an entrance ramp to a freeway, waiting for a break in the traffic. Then the driver accelerates with constant acceleration along the ramp and onto the freeway. The car starts from rest, moves in a straight line, and has a speed of 20 m/s 145 mi/h2 when it reaches the end of the 120-m-long ramp. (a) What is the acceleration of the car? (b) How much time does it take the car to travel the length of the ramp? (c) The traffic on the freeway is moving at a constant speed of 20 m/s.What distance does the traffic travel while the car is moving the length of the ramp?
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