| Difficulty | Secondary School | High school/other |
| ★ | Basic | Easy |
| ★★ | Demanding | Basic |
| ★★★ | Demanding | |
| ★★★★ | Difficult | |
| ★★★★★ | Very difficult |
Determine the coefficient of static friction between the body and the substrate.
Answer: 0,77
Exercise 3.9 C
| Difficulty | Secondary School | High school/other |
| ★ | Basic | Easy |
| ★★ | Demanding | Basic |
| ★★★ | Demanding | |
| ★★★★ | Difficult | |
| ★★★★★ | Very difficult |
Determine the coefficient of kinetic friction between the body and the substrate.
Answer: 0,59
Exercise 3.9 D
| Difficulty | Secondary School | High school/other |
| ★ | Basic | Easy |
| ★★ | Demanding | Basic |
| ★★★ | Demanding | |
| ★★★★ | Difficult | |
| ★★★★★ | Very difficult |
Specify the coefficient of static friction.
Answer: 0,25
Exercise 3.9 E
| Difficulty | Secondary School | High school/other |
| ★ | Basic | Easy |
| ★★ | Demanding | Basic |
| ★★★ | Demanding | |
| ★★★★ | Difficult | |
| ★★★★★ | Very difficult |
a) How many percents of the bodys potential energy transforms to heat energy during the sliding? b) Specify the coefficient of the sliding friction.
Tip 1: Measure time and velocity at specific distance.
Tip 2: The principle of energy $E_{beginning}=E_{end}$ or the model of steady accelerating movement.
Tip 2: The principle of energy $E_{beginning}=E_{end}$ or the model of steady accelerating movement.
Answer: a) 95 % - 96 %; b) 0,22 – 0,24
Exercise 3.9 F
| Difficulty | Secondary School | High school/other |
| ★ | Basic | Easy |
| ★★ | Demanding | Basic |
| ★★★ | Demanding | |
| ★★★★ | Difficult | |
| ★★★★★ | Very difficult |
Determine the coefficient of sliding friction between the surface and the body.
Answer: $0{,}14$
Exercise 3.10 A
| Difficulty | Secondary School | High school/other |
| ★ | Basic | Easy |
| ★★ | Demanding | Basic |
| ★★★ | Demanding | |
| ★★★★ | Difficult | |
| ★★★★★ | Very difficult |
How much (percentage) of the ball's potential energy is converted into thermal energy in the collision?
Answer: 54 %
Exercise 3.11 A
| Difficulty | Secondary School | High school/other |
| ★ | Basic | Easy |
| ★★ | Demanding | Basic |
| ★★★ | Demanding | |
| ★★★★ | Difficult | |
| ★★★★★ | Very difficult |
Determine the mass of the load to be lifted.
Answer: 187,2 g
Exercise 3.11 B
| Difficulty | Secondary School | High school/other |
| ★ | Basic | Easy |
| ★★ | Demanding | Basic |
| ★★★ | Demanding | |
| ★★★★ | Difficult | |
| ★★★★★ | Very difficult |
Determine the mass of the yellow metal bar.
Answer: 109,9 g
Exercise 3.11 C
| Difficulty | Secondary School | High school/other |
| ★ | Basic | Easy |
| ★★ | Demanding | Basic |
| ★★★ | Demanding | |
| ★★★★ | Difficult | |
| ★★★★★ | Very difficult |
There is a wire wrapped around a metal bar in the video. Determine the coefficient of static friction between the wire and the metal bar.
Tip: Google "capstan equation"
Answer: 0,11
Exercise 3.11 D
| Difficulty | Secondary School | High school/other |
| ★ | Basic | Easy |
| ★★ | Demanding | Basic |
| ★★★ | Demanding | |
| ★★★★ | Difficult | |
| ★★★★★ | Very difficult |
Demonstrate the validity of the laws of statics by comparing the measurement results with the values obtained by calculation.
Answer: It is stated that the measured force values are very close to the calculated values.