III.4. Recapitulative exercises - Movement and Rest
🔐 Recapitulative exercises - Movement and Rest.
1. Determine whether the following statements are true (A) or false (F):
a) A house is at rest relative to the sun.
b) The bus driver is at rest in front of the passengers in the seats.
c) An airplane is in a state of motion relative to the ground.
d) The average speed is the arithmetic mean of the momentary velocities of the mobile.
e) A body is in accelerated rectilinear motion.
f) A mobile has a rotational motion when its trajectory is a circle.
g) In uniform rectilinear motion the mobile travels equal distances in equal time intervals.
h) The graph of uniform rectilinear motion is a straight line.
i) When a body starts it has a slow motion.
j) When a body stops it has an accelerated movement.
2. Which of the following mobiles has the highest average speed: the first mobile that traveled a distance of 600 hm in 0,3 h or the second mobile that traveled a distance of 50 km in 50 min?
3. Transform the following speeds into SI:
a) v = 5400 dam/h
b) v = 300 dm/min
4. Transform the following accelerations into SI:
a) a = 240 cm/min2
b) a = 7800 km/h2
5. Look carefully at the following graph:
a) What kind of movement does the mobile have? Why ?
b) Fill in the table with the data of the mobile movement.
c) Determine on the graph the time at position x = 125 km.
d) Determine on the graph the position at t = 0.75 h.
e) Calculate the average speed of the mobile.
f) Write the law of motion of this mobile.
6. The following table gives the data of the movement of two mobiles M1 și M2.
a) Determine the positions of the mobile M2, knowing the law of motion:
xM2 = 20 + 2 ∙ t
b) Make the graphs of the motion of the two mobiles. Standards: 1 cm: 40 hm, 1 cm: 10 min.
c) What is the position of the two mobiles at t = 30 min?
d) Determine the average speeds of the two mobiles.
e) Write the law of motion for the mobile M1.
7. What is the acceleration of a Formula 1 car that reaches a speed of 100 km / h in 2 s at start-up?