Explanation:
(a) Displacement of an object is the shortest path covered by it.
In this problem, a student is biking to school. She travels 0.7 km north, then realizes something has fallen out of her bag. She travels 0.3 km south to retrieve her item. She then travels 0.4 mi north to arrive at school.
0.4 miles = 0.64 km
displacement = 0.7-0.3+0.64 = 1.04 km
(b) Average velocity = total displacement/total time
t = 15 min = 0.25 hour
Hence, this is the required solution.
Answer:
-6327.45 Joules
650.375 Joules
378.47166 N
Explanation:
h = Height the bear slides from = 15 m
m = Mass of bear = 43 kg
g = Acceleration due to gravity = 9.81 m/s²
v = Velocity of bear = 5.5 m/s
f = Frictional force
Potential energy is given by
Change that occurs in the gravitational potential energy of the bear-Earth system during the slide is -6327.45 Joules
Kinetic energy is given by
Kinetic energy of the bear just before hitting the ground is 650.375 Joules
Change in total energy is given by
The frictional force that acts on the sliding bear is 378.47166 N
Answer:
a.73.3%
b.26.6%
Explanation:
a. The efficiency is the energy output, divided by the energy input, and expressed as a percentage.
#Given the energy input as 1500J and the subsequent output as 1100J, the TV's efficiency is calculated as:
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Hence, the TV has an efficiency of 33.3%
b. From a above, we know that the TV has an output of 1100J and input of 1500J.
-We therefore calculate it's wastage as the difference between output and input:
<em>Wastage=Energy Input-Energy Output=1500J-1400J=400J</em>
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Hence, the TV has wasted of 26.6%