k = 1/2 × m × v^2
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1. k = 1/2 × 60 × ( 10 )^2
k = 30 × 100
k = 3000 j
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2. k = 1/2 × 60 × ( 9 )^2
k = 30 × 81
k = 2430 j
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3. k = 1/2 × 60 × ( 4 )^2
k = 30 × 16
k = 480 j
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4. k = 1/2 × 60 × ( 6 )^2
k = 30 × 36
k = 1080 j
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5. k = 1/2 × 60 × ( 0 ) ^2
k = 30 × 0
k = 0 j
Answer:
0.83m/s
Explanation:
Given parameters:
distance = 1000m
time taken = 20min
Unknown:
Speed of the walking person = ?
Solution:
To solve this problem;
Speed = 
Time taken should be in seconds;
1 min = 60s
20min = 20 x 60 = 1200s
Speed = 
= 0.83m/s
Potential energy is a relative measure, so the answer is dependent on the assumptions we make. The potential energy in the car is going to be gravitational potential energy(PE). PE = mgh, where m is the mass, g is 9.8 m/s^2, and h is the height. So PE = 2000*9.8*h = 19600h. The final answer obviously depends on h. Most likely the problem is assuming that 30 meters under the top of the hill is considered 0 meters. Then h would be 30m and PE would equal 588 kJ.
Answer:
13 m
Explanation:
It is given that :
I got a haircut sitting at a place having two parallel mirrors at a distance = 6.5 m apart
My head is at a distance of 2 m from the nearer mirror.
Now the light from the back of my head must go to (6.5 - 2) = 4.5 m to the back mirror.
Then it must go to 6.5 m to the front mirror and 2 m from the front mirror to my eyes.
So in order to see the back of my head, it will be = 6.5 + 2 + 4.5 = 13 m away.
Answer:
Explanation:
We shall apply conservation of mechanical energy
kinetic energy of alpha particle is converted into electric potential energy.
1/2 mv² = k q₁q₂/d , d is closest distance
d = 2kq₁q₂ / mv²
= 2 x 9 x 10⁹ x 79e x 2e / 4mv²
= 1422 x2x (1.6 x 10⁻¹⁹)² x 10⁹ /4x 1.67 x 10⁻²⁷ x (1.5 x 10⁷)²
= 3640.32 x 10⁻²⁹ /2x 3.7575 x 10⁻¹³
= 484.4 x 10⁻¹⁶
=48.4 x 10⁻¹⁵ m
