Answer:
4.25 s
Explanation:
Given:
angular acceleration'α'= 1.8 rad/s²
angle 'θ'= 45 rad
time 't'= 4s
initial angular velocity '
'=0
as we know that,
θ= 
t + 
45 = 4 + (0.5 x 1.8 x 16)
45- 14.4 = 4
30.6 = 4
= 7.65
Next is to find t by using the equation
= + 
7.65= 0 + (1.8)
= 7.65/1.8
= 4.25 s
Therefore, At the start of 4s interval the motion is at 4.25 second
Answer:
-0.55m/s
Explanation:
Given that: For the boy
Weight = 745N
Velocity = +0.35 m/s
Mass of the boy = ?
g = 9.81m/s^2
W = mg
745 = m×9.81
m = 75.94kg
For the girl
Given that:
Weight = 477 N
g = 9.81m/s^2
m = ?
W = mg
477 = m×9.81m/s^2
m = 48.62kg
To solve for the v of the girl, the two has to add up
48.62kg×v + 75.94kg×+0.35 m/s = 0
48.62v + 26.579 = 0
48.62v = - 26.579
v = -26.579/48.62
v = -0.5466
v = -0.55m/s
Hence, the velocity of the girl is -0.55m/s.
The negative sign is as a result of the two of them moving is opposite direction.
Answer:
<h2>9.3kN</h2>
Explanation:
Step one:
given data
mass of bullet= 0.02kg
speed v=700m/s
time taken =1.5ms= 0.0015 seconds
Step two:
we know that from the first law
F=ma-----1 first law of motion
also, we know that
a=v/t----2
put a=v/t in equation 1 we have
F=mv/t
Step three:
substitute our given data to find force
F=0.02*700/0.0015
F=14/0.0015
F=9333.33N
F=9.3kN
<u>The average force exerted is 9.3kN</u>
Force applied = F = 628 N
<span>Acceleration = a m/s² </span>
<span>Newton's 2nd law of motion : F = Ma </span>
<span> a = F/M -------- (1) </span>
<span>New mass of the crate = M1 = 3.8M kg </span>
<span>New acceleration = a1 = F/M1 = F/(3.8 M) ----- (2) </span>
<span>a1/a = {F/(3.8M)}/(F/M) = 1/3.8 = 10/38 = 5/19 ------- Answer</span>
