Physics, 03.04.2020 00:00 Jaimewillis42
Usain Bolt's world-record 100 m sprint on August 16, 2009, has been analyzed in detail. At the start of the race, the 94.0 kg Bolt accelerated from rest at a rate of 9.50 m/s^2 for the first 0.890 s, and eventually reached a top speed of 12.4 m/s by exerting an average horizontal force of 820 N against the ground for the entire 9.58 s duration of the race. a. What was the average horizontal force (in N) exerted by Bolt against the ground during the first 0.890 s of the race?b. What was Bolt's speed (in m/s) after the initial acceleration phase?c. What was the power expended by Bolt during the initial acceleration phase?d. It has been shown that, because of his large frame and 6'5" height, Bolt experienced significant drag forces during the sprint. To estimate the energy lost to drag forces during the race, let's focus on the remaining 9.58 s − 0.890 s = 8.69 s of the race after Bolt's initial burst of acceleration. The drag force varies with speed, but let's find an average drag force over the last 8.69 s of the race. Model the drag force as a friction force and find the increase in internal energy of Bolt and the surrounding air in these 8.69 s as Bolt runs through the air. e. Finally, find the power that Bolt must expend just to overcome the drag force and compare it to the result in part (c).
Answers: 2
Physics, 22.06.2019 00:30
Glass is transparent to visibile light under normal conditions; however, at extremely high intensities, glass will absorb most of the light incident upon it. this works through a process known as multiphoton absorption. in this process, several photons are absorbed at the same time. if very intense light whose photons carry 2ev of energy is shined onto a material with a band gap of 4ev, that light can be absorbed through two-photon absorption, because two photons have the right amount of energy to bridge the band gap. what is the minimum number of photons of 800-nm light that are needed to equal or exceed the band gap of fused silica glass
Answers: 1
Physics, 22.06.2019 00:30
Consider an ordinary, helium-filled party balloon with a volume of 2.2 ft3. the lifting force on the balloon due to the outside air is the net resultant of the pressure distribution exerted on the exterior surface of the balloon. using this fact, we can derive archimedes’ principle, namely that the upward force on the balloon is equal to the weight of the air displaced by the balloon. assuming that the balloon is at sea level, where the air density is 0.002377 slug/ft3, calculate the maximum weight that can be lifted by the balloon. note: the molecular weight of air is 28.8 and that of helium is 4.
Answers: 2
Physics, 22.06.2019 09:20
Question 11 of 13 (1 point) jump to question: a stairway, ladder, or ramp must be present in excavations in which of the following situations? a. all trenches must have access/egress b. the trench is more than 15 feet wide but only 1 ½ feet deep c. the trench is more than 4 feet deep and the devices must be within 25 feet of all workers
Answers: 1
Physics, 22.06.2019 14:40
The experiment done in lab is repeated, using a ball that has unknown mass m. you plot your data in the form of f 2 versus m/l, with f in rev/s, m in kg, and l in m. your data falls close to a straight line that has slope 3.19 m/(kg · s2). use g = 9.80 m/s2 and calculate the mass m of the ball.
Answers: 1
Usain Bolt's world-record 100 m sprint on August 16, 2009, has been analyzed in detail. At the start...
Mathematics, 07.12.2021 18:50
Social Studies, 07.12.2021 18:50
Advanced Placement (AP), 07.12.2021 18:50
Computers and Technology, 07.12.2021 18:50
English, 07.12.2021 18:50
Mathematics, 07.12.2021 18:50
Mathematics, 07.12.2021 18:50
Mathematics, 07.12.2021 18:50
Social Studies, 07.12.2021 18:50
Computers and Technology, 07.12.2021 18:50