Answer:
<h3>130N</h3>
Explanation:
according to Newtons second law;
F = ma
F = m(v-u)/t
m is the mass = 60+5 = 65kg
v is the final velocity = 0m/s
initial velocity = 8m/s
time t = 4.0s
F = 65(8)/4
F = 65*2
F = 130N
Hence he applied a force of 130N
Answer:
<h2>42 N</h2>
Explanation:
The force acting on an object given it's mass and acceleration can be found by using the formula
force = mass × acceleration
From the question
mass = 7 kg
acceleration = 6 m/s²
We have
force = 7 × 6 = 42
We have the final answer as
<h3>42 N</h3>
Hope this helps you
I think it is c
But there could be some other people that think differently
Answer:
15186 J energy lost due to friction
Explanation:
Given:
- Height of the tallest hill (first) h_1 = 16 m
- Height of the last hill h_2 = 7 m
- Velocity @tallest hill = 0
- Velocity @last hill = 0
Find:
How much energy was lost due to friction can be determined from an energy balance at point on top of tallest hill and on top of last hill:
E_p,1 + E_k,1 = E_p,2 + E_k,2 + E_f
Where, E_k,1 = E_k,2 = 0
E_p,1 - E_p,2 = E_f
E_f = m*g*(h_1 - h_2)
E_f = 172*9.81*(16 - 7)
E_f = 15186 J