Answer:
3120J
Explanation:
Given parameters:
C = Specific heat capacity = 0.8J/g°C
Initial temperature = 20°C
Mass given = 5g
Final temperature = 800°C
Unknown:
Energy given to the mass = ?
Solution:
To find the energy given to the mass, let us simply use the expression below:
H = m c ΔT
H is the unknown, the energy supplied
m is the mass of the substance
c is the specific heat capacity
ΔT is the change in temperature
Input the variables;
H = 5 x 0.8 x (800 - 20) = 3120J
Answer:
51.85m/s
Explanation:
Given parameters:
Mass of ball = 0.0459kg
Force = 2380N
Time taken = 0.001s
Unknown:
Speed of the ball afterwards = ?
Solution:
To solve this problem, we use Newton's second law of motion:
F = m x
F is the force
m is the mass
v is the final velocity
u is the initial velocity
t is the time taken
2380 = 0.0459 x
0.0459v = 2.38
v = 51.85m/s
That can be considered alive.
The force exerted by a magnetic field on a wire carrying current is:

where I is the current, L the length of the wire, B the magnetic field intensity, and

the angle between the wire and the direction of B.
In our problem, the force is F=0.20 N. The current is I=1.40 A, while the length of the wire is L=35.0 cm=0.35 m. The angle between the wire and the magnetic field is

, so we can re-arrange the formula and substitute the numbers to find B: