CONSTANT ACCELERATION
DRBN02E - DYNAMICS OF RIGID BODIES
PREPARED BY: ENGR. BENS HE DIROY
KINEMATICS
It is the study of the geometry of motion of
particles, rigid bodies, etc., disregarding the
forces associated with these motions.
Kinematics of a particle in space motion of a
point Interest is on defining quantities such
as position, velocity, and acceleration.
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DERIVED FORMULAS FOR
RECTILINEAR MOTION​
CONSTANT ACCELERATION:
𝑉𝑓 = 𝑉𝑜 + 𝑎𝑡
1 2
∆𝑥 = 𝑉𝑜 𝑡 + 𝑎𝑡
2
𝑉𝑓2 = 𝑉𝑜2 + 2𝑎∆𝑥
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SAMPLE PROBLEM #1
A truck traveling along a straight road at speed of
20 kph, increases its speed to 120kph in 15 sec.
a. What is the constant acceleration? (1.85 m/s2)
b. Determine the total distance travelled.
(291.67m)
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SAMPLE PROBLEM #2
An automobile starting from rest speeds up to 40
m/s with a constant acceleration of 4 m/s2, runs
at this speed for a time, and finally comes rest
with deceleration of 5 m/s2. If the total distance
travelled is 1000m,
a. Find the distance covered during the
acceleration. (200 m)
b. Find the distance travelled at constant speed.
(640 m)
c. Find the total time of travel. (34 sec)
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SAMPLE PROBLEM #3
An automobile is driven at 30 mph for 12 min,
then at 40 mph for 20 min, and finally at 50 mph
for 8 min.
a. Calculate the average speed over the interval
in mph. (39 mph)
b. How fast must the automobile move in the last
8 min to obtain an average speed of 35 mph?
(15 mph)
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SAMPLE PROBLEM #4
Car A at gasoline station stays there for 10 minutes
after a car B passes at an average speed of 40
mph.
a. How long will it take car A moving at an average
speed of 50mph to overtake car B? (40 mins)
b. What is the total distance traveled by car A to
overtake car B? (33.33 mi)
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SAMPLE PROBLEM #5
On a certain stretch of track, trains run at 60 mph
(96.56 kph). How far back of a stopped train should
be a warning torpedo be placed to signal an
oncoming train? Assume that the brakes are applied
at once and retard the train at the uniform rate of
2 ft/sec (0.61 m/s2).
2
S= 589.698 m
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