please help me solve this problem !! With an initial velocity of 20m/s. A car accelerated at 30m/s 2 for 15 seconds. What is the position of the car at the end of 10 seconds?
From rest, a car accelerated at 8 m/s2 for 10 seconds.
a) What is the position of the car at the end of the 10 seconds?
Solution to Problem 1:
a) The car starts from rest therefore the initial speed u = 0. Nothing is said about the initial position and we therefore assume it is equal to 0. Hence the position x is given by the equation
x = (1/2) a t 2
where a is the acceleration (=8 m/s2) and t is the period of time between initial and final positions
x = (1/2)8 (10)2 = 400 m
Problem 2:
With an initial velocity of 20 km/h, a car accelerated at 8 m/s2 for 10 seconds.
a) What is the position of the car at the end of the 10 seconds?
Solution to Problem 2:
a) The car has an initial velocity of 20 km/h, therefore the initial speed u = 20 km/h. Nothing is said about the initial position and we therefore assume it is equal to 0. Hence the position x is given by the equation
x = (1/2) a t 2 + u t
where a is the acceleration (=8 m/s2) and t is period of time between initial and final positions and u is the initial velocity.
Since the time is given in seconds, we need to convert 20 km/h into m/s as follows:
Answers & Comments
Answer:
Problem 1:
From rest, a car accelerated at 8 m/s2 for 10 seconds.
a) What is the position of the car at the end of the 10 seconds?
Solution to Problem 1:
a) The car starts from rest therefore the initial speed u = 0. Nothing is said about the initial position and we therefore assume it is equal to 0. Hence the position x is given by the equation
x = (1/2) a t 2
where a is the acceleration (=8 m/s2) and t is the period of time between initial and final positions
x = (1/2)8 (10)2 = 400 m
Problem 2:
With an initial velocity of 20 km/h, a car accelerated at 8 m/s2 for 10 seconds.
a) What is the position of the car at the end of the 10 seconds?
Solution to Problem 2:
a) The car has an initial velocity of 20 km/h, therefore the initial speed u = 20 km/h. Nothing is said about the initial position and we therefore assume it is equal to 0. Hence the position x is given by the equation
x = (1/2) a t 2 + u t
where a is the acceleration (=8 m/s2) and t is period of time between initial and final positions and u is the initial velocity.
Since the time is given in seconds, we need to convert 20 km/h into m/s as follows:
u = 20 km/h =
20 * 1km
1 hour
1000 m
1 km
1 hour
3600 seconds
= 5.6 m/s