I believe the last one about the bike is correct.
Answer:
4.45×10¯¹¹ N
Explanation:
From the question given above, the following data were obtained:
Mass of ball (M₁) = 4 Kg
Mass of bowling pin (M₂) = 1.5 Kg
Gravitational constant (G) = 6.67×10¯¹¹ Nm²/Kg²
Distance apart (r) = 3 m
Force of attraction (F) =?
The force of attraction between the ball and the bowling pin can be obtained as follow:
F = GM₁M₂ / r²
F = 6.67×10¯¹¹ × 4 × 1.5 / 3²
F = 4.002×10¯¹⁰ / 9
F = 4.45×10¯¹¹ N
Therefore, the force of attraction between the ball and the bowling pin is 4.45×10¯¹¹ N
Answer:
(a)11.24 m/s
(b)7.44 m/s
(c)409 N
(d)
(e) 0
Explanation:
The period for 1 circle
of the merry go around is 9.5s. It means the angular speed is:

(a)The speed is

(b) Centripetal acceleration:

(c) Magnitude of the force that keeps you go around at this acceleration

(d) let the coefficient of friction by
. The frictional force shall be this coefficient multiplied by normal force reverting gravity of the man

The relative density of gold is 19.3 it means the ratio obtained by dividing the density of gold by water at temp of 4 degree celcius is 19.3
Answer:17.08 s
Explanation:
Given
distance between First and second Runner is 45.6 m
speed of first runner
=3.1 m/s
speed of second runner
=4.65 m/s
Distance between first runner and finish line is 250 m
Second runner need to run a distance of 250+45.6=295.6 m
Time required by second runner 
time required by first runner to reach finish line
Thus second runner reach the finish line 80.64-63.56=17.08 s earlier