Answer:
400 N
Explanation:
From the question,
F = kmm'/r²........................ Equation 1
Where F = gravitation force, m and m' = mass 1 and mass 2 respectively, r = distance between the masses.
Given; F = 800 N
Substitute these values into equation 1
800 = kmm'/r².............. Equation 2
If the distance is doubled (2r), and one of the mass is doubled (2m), The new force is
F' = k(2m)(m')/(2r)²
F' = 2kmm'/4r²
F' = kmm'/2r²................. Equation 3
Comparing equation 2 and equation 3
F' = F/2............................ Equation 4
Substitute the value of F into equation 4
F' = 800/2
F' = 400 N
Answer:
c. covering
Explanation:
covering is just doing defence and is not illegal in basketball
Answer:
4.8 m/s
Explanation:
When she catches the train,
- They will have travelled the same distance.and
- Their speeds will be equal
The formula for the distance covered by the train is
d = ½at² = ½ × 0.40t² = 0.20t²
The passenger starts running at a constant speed 6 s later, so her formula is
d = v(t - 6.0)
The passenger and the train will have covered the same distance when she has caught it, so
(1) 0.20t² = v(t - 6.0)
The speed of the train is
v = at = 0.40t
The speed of the passenger is v.
(2) 0.40t = v
Substitute (2) into (1)
0.20t² = 0.40t(t - 6.0) = 0.40t² - 2.4 t
Subtract 0.20t² from each side
0.20t² - 2.4t = 0
Factor the quadratic
t(0.20t - 2.4) = 0
Apply the zero-product rule
t =0 0.20t - 2.4 = 0
0.20t = 2.4
(3) t = 12
We reject t = 0 s.
Substitute (3) into (2)
0.40 × 12 = v
v = 4.8 m/s
The slowest constant speed at which she can run and catch the train is 4.8 m/s.
A plot of distance vs time shows that she will catch the train 6 s after starting. Both she and the train will have travelled 28.8 m. Her average speed is 28.8 m/6 s = 4.8 m/s.
A. Blocking light waves that vibrate in the plane. (?)
Answer:
Evan drive at speed = 81.67 m/hr
Explanation:
Normal speed of Evan = 70 m/hr
Time taken by Evan to visit his grandmother = 35 min = hr
Distance covered by Evan = =
= miles
According to the problem, one day Evan was running 5 minutes late. So, the time Evan has to visit his grandmother is 30 mins.
To reach on time, Evan should be drive at the speed :
Speed =
=
= 81.67 m/hr