Answer:
Potential energy of book = 7.5 J
Explanation:
Given:
Weight of book = 5 N
Height of shelf = 1.5 meter
Find:
Potential energy of book
Computation:
Weight = Mass x Acceleration of gravity
Mass x Acceleration of gravity = 5 N
Potential energy = Mass x Acceleration of gravity x Height
Potential energy of book = Mass x Acceleration of gravity x Height
We know that;
Mass x Acceleration of gravity = 5 N
So,
Potential energy of book = 5 x 1.5
Potential energy of book = 7.5 J
Given that,
The acceleration of gravity is -9.8 m/s²
Initial velocity, u = 39.2 m/s
Time, t = 2 s
To find,
The final velocity of the shot.
Solution,
Let v is the final velocity of sling shot. Using first equation of motion to find it.
v = u +at
Here, a = -g
v = u-gt
v = (39.2)-(9.8)(2)
v = 19.6 m/s
So, its velocity after 2 seconds is 19.6 m/s.
Answer:
15.5 m/s.
Explanation:
Potential energy of the balloon has been converted to kinetic energy.
potential energy = kinetic energy.
mgh = ½mv².
10* 10* 12= ½ *10 *v²
1200 = 5v²
v²=1200÷5
v=√240
v= 15.49~15.5 m/s.
Answer:
1.40 N
Explanation:
The magnitude of the frictional force is given by:
where
is the coefficient of friction
N is the magnitude of the normal reaction
The coefficient of friction for this problem is 
. The magnitude of the normal reaction is equal to the combined weight of the boy and the sled, because the surface is horizontal, so
Therefore, the frictional force is
Induced motion or movement
