Podcast
Questions and Answers
What is the relationship between the changes in lengths Δ𝐿 and Δ𝐿 when the same stress is applied on both strings?
What is the relationship between the changes in lengths Δ𝐿 and Δ𝐿 when the same stress is applied on both strings?
- Δ𝐿 = 4Δ𝐿
- Δ𝐿 = Δ𝐿
- Δ𝐿 = Δ𝐿 (continued on next page)
- Δ𝐿 = 2Δ𝐿 (correct)
When an apple thrown up with a velocity 𝑢 = 12 𝑚/𝑠 crosses a tree branch at a height ℎ = 6𝑚, what are the times 𝑡 it takes to cross the branch on the way up and on the way down?
When an apple thrown up with a velocity 𝑢 = 12 𝑚/𝑠 crosses a tree branch at a height ℎ = 6𝑚, what are the times 𝑡 it takes to cross the branch on the way up and on the way down?
- 𝑡 = 0.7; 𝑡 = 6.8
- 𝑡 = 0.7; 𝑡 = 3.4 (correct)
- 𝑡 = 0.7; 𝑡 = 1.7
- 𝑡 = 0.7; 𝑡 = 5.1
A car moving at 60 km/h to the right stops in 25 m when brakes are applied. What distance is the kinetic energy of the car half its initial kinetic energy?
A car moving at 60 km/h to the right stops in 25 m when brakes are applied. What distance is the kinetic energy of the car half its initial kinetic energy?
- 25/4 m (correct)
- 25/16 m
- 25/2 m
- 25/8 m
If a person weighing 70 kg stands on a weighing scale and compresses the spring by 0.1 cm at home, what is the compression of the spring in an elevator accelerating upwards at 1.2 m/s²?
If a person weighing 70 kg stands on a weighing scale and compresses the spring by 0.1 cm at home, what is the compression of the spring in an elevator accelerating upwards at 1.2 m/s²?
A 2 kg ball is thrown straight up with a speed of 10 m/s. What force 𝐹 is required to catch the ball when it returns if your hand moves down by 15 cm once the ball falls in your hand?
A 2 kg ball is thrown straight up with a speed of 10 m/s. What force 𝐹 is required to catch the ball when it returns if your hand moves down by 15 cm once the ball falls in your hand?
If a 2 kg ball is dropped from a height of ℎ = 3 m, what is the gravitational potential energy of the ball when it is dropped?
If a 2 kg ball is dropped from a height of ℎ = 3 m, what is the gravitational potential energy of the ball when it is dropped?
What force is needed to catch the ball when it reaches the ground?
What force is needed to catch the ball when it reaches the ground?
How many kilocalories are required for a 70 kg person to walk 4000 m on level ground?
How many kilocalories are required for a 70 kg person to walk 4000 m on level ground?
What is the cross-sectional area of the DNA molecule that requires a force of 60 pN to stretch by 12% of its original length?
What is the cross-sectional area of the DNA molecule that requires a force of 60 pN to stretch by 12% of its original length?
If the hand moves down by 20 cm instead of 15 cm when catching the ball, what force would be needed?
If the hand moves down by 20 cm instead of 15 cm when catching the ball, what force would be needed?
How much additional energy is required if a 70 kg person walks at a 45-degree angle instead of horizontally for 4000 m?
How much additional energy is required if a 70 kg person walks at a 45-degree angle instead of horizontally for 4000 m?
When a person weighing 70 𝑘𝑔 climbs stairs to work off extra calories, how much total energy is expended if each stair is 15 𝑐𝑚 high? (in kcal)
When a person weighing 70 𝑘𝑔 climbs stairs to work off extra calories, how much total energy is expended if each stair is 15 𝑐𝑚 high? (in kcal)
If the power consumed by the organs during rest is 85 𝑊, how much energy is consumed in 24 hours of resting? (in 𝑘𝑐𝑎𝑙)
If the power consumed by the organs during rest is 85 𝑊, how much energy is consumed in 24 hours of resting? (in 𝑘𝑐𝑎𝑙)
If a spring inside a weighing scale compresses by 0.1 𝑐𝑚 when a 70 𝑘𝑔 person stands on it, what is the potential energy stored in the compressed spring? (in J)
If a spring inside a weighing scale compresses by 0.1 𝑐𝑚 when a 70 𝑘𝑔 person stands on it, what is the potential energy stored in the compressed spring? (in J)
For a person weighing 70 𝑘𝑔, how many stairs approximately need to be climbed to burn the energy equivalent to sleeping for 8 hours? (Find the closest integer number of steps.)
For a person weighing 70 𝑘𝑔, how many stairs approximately need to be climbed to burn the energy equivalent to sleeping for 8 hours? (Find the closest integer number of steps.)
Considering an average adult male femur that can support up to 30 times his weight, if the weight of an average adult male is 196 𝑙𝑏, what is the maximum force the femur can support? (in N)
Considering an average adult male femur that can support up to 30 times his weight, if the weight of an average adult male is 196 𝑙𝑏, what is the maximum force the femur can support? (in N)
Two strings made of the same material have one twice longer and twice bigger cross-sectional area than the other. If a force is applied, which string will experience a higher strain?
Two strings made of the same material have one twice longer and twice bigger cross-sectional area than the other. If a force is applied, which string will experience a higher strain?
