PHYSICS – problem solving exercises
1. Kinematics: one-dimensional motion
Problem 1:
During a hard sneeze, your eyes might shut for 0.50 s. If you are driving a car at 90 km/h during such a
sneeze, how far does the car move during that time?
Problem 2:
An automobile travels on a straight road for 40 km at 30 km/h. It then continues in the same direction for
another 40 km at 60 km/h.
(a) What is the average velocity of the car during the full 80 km trip? (Assume that it moves in the positive
x direction.)
(b) What is the average speed?
Problem 3:
An automobile travels on a straight road for 40 km at 30 km/h. It then continues in the opposite direction
for another 40 km at 60 km/h.
(a) What is the average velocity of the car during the full 80 km trip?
(b) What is the average speed?
Notes: magnitude of free fall acceleration g = 10 m/s2
, air friction is neglected in all cases
Problem 4:
A speed of a bullet fired from the 1.2 m long gun barrel is 640 m/s. How long is the bullet accelerated in
the barrel? (Assume motion with constant acceleration).
Problem 5:
A car accelerates from rest with a constant acceleration for 0.5 minutes. It travels 150 m during this time.
What is its velocity now?
Problem 6:
A jet plane takeoff speed must be at least 360 km/h. What is a minimal constant acceleration for takeoff
using the 1.8 km long runway?
Problem 7:
A car starts to decelerate from an initial velocity of +20 m/s and stops after 4 s. What is its acceleration
(magnitude and direction)?
Problem 8:
A car uniformly accelerates from rest with an acceleration of 5 m/s2
. What is its velocity after traveling to a
distance of 90 m from the starting point?
Problem 9:
A uniformly accelerating car (a = 6 m/s2
) increased its velocity to 35 m/s in time of 4 s. What was its initial
velocity?
Problem 10:
A car accelerates from rest with a uniform acceleration. After traveling a distance of 160 m its velocity is
26 m/s. What is its acceleration?
Problem 11:
A jet plane lands with a speed of 100 m/s and can accelerate at a maximum rate of -5 m/s2
as it comes to
rest. Can this plane land at a small airport where the runway is 0.8 km long?
Problem 12:
A landing jet plane stops after 1 min at the end of a 2.4 km long runway. What was its initial speed before
landing?
Problem 14:
A stone is thrown upwards from Earth’s surface with an initial velocity of 18 m/s. What is the maximal
height reached by the stone?
Problem 15:
A ball was dropped from a top of a building. Its impact speed was 14 m/s.
(a) How long did it fall?
(b) How high is the building?
Problem 13:
A a construction site a pipe wrench struck the ground with a speed of 24 m/s.
(a) From what height was it inadvertently dropped?
(b) How long was it falling?
Problem 16:
A freely falling ball of 0.5 kg mass reaches the ground at time 1.5 s. From what height was it dropped?
Problem 18:
A stone was thrown downwards from a height of 30 m and reached the ground after 2 s. What was its
initial speed?
Problem 17:
A stone is thrown upwards from a ground with an initial velocity of 20 m/s.
(a) When does it get to the maximal height?
(b) What is its final speed at impact?
Problem 19:
A rock is thrown vertically upward from ground level at time t = 0. At t = 1.5 s it passes the top of a tall
tower, and 1.0 s later it reaches its maximum height. What is the height of the tower?
Problem 20:
A car traveling 56.0 km/h is 24.0 m from a barrier when the driver slams on the brakes. The car hits the
barrier 2.00 s later.
(a) What is the magnitude of the car‘s constant acceleration before impact?
(b) How fast is the car traveling at impact?
Problem 21:
A hoodlum throws a stone vertically downward with an initial speed of 12.0 m/s from the roof of a
building, 30.0 m above the ground.
(a) How long does it take the stone to reach the ground?
(b) What is the speed of the stone at impact?