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:
b.) Length
Explanation:
The length of the string can be changed by removing it from the slotted bracket and placing it back in. You can change the mass by varying the number of washers on the mass hanger. The amplitude can be changed by varying the starting angle of the pendulum (low, medium, and high angle). sorry if wrong
Answer:
Atomic size
Explanation:
In the periodic table , atomic size is indirectly proportional to the effective nuclear charge .the atomic size reduces from left to right across the table. This is because electrons are added to the same shell.
<h2>
Kinetic energy of mass 4 kg ball is less than kinetic energy of mass 2 kg ball</h2>
Explanation:
Kinetic energy = 0.5 x Mass x Velocity²
For ball of mass 2 kg
Mass, m = 2 kg
Velocity, v = 4 m/s
Kinetic energy = 0.5 x 2 x 4² = 16 J
For ball of mass 4 kg
Mass, m = 4 kg
Velocity, v = 2 m/s
Kinetic energy = 0.5 x 4 x 2² = 8 J
Kinetic energy of mass 4 kg ball is less than kinetic energy of mass 2 kg ball
Give u = start velocity
v = end velocity
v = u + at
50 = 400 + a*30
30a = -350
a = -116.67 m/
**Why the accecleration is negative number**
Because displacement, velocity, and acceleration are VECTOR QUANTITIES.
Vector Quantity must have direction.
