[FEAT] Add Kinematics (SUVAT) equations

src/main/java/com/thealgorithms/physics/Kinematics.java

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+package com.thealgorithms.physics;
+/**
+ * Implements the fundamental "SUVAT" equations for motion
+ * under constant acceleration.
+ *
+ * @author [Priyanshu Kumar Singh](https://github.com/Priyanshu1303d)
+ * @see <a href="https://en.wikipedia.org/wiki/Equations_of_motion#Uniform_acceleration">Wikipedia</a>
+ */
+public final class Kinematics {
+    private Kinematics() {
+    }
+
+    /**
+     * Calculates the final velocity (v) of an object.
+     * Formula: v = u + at
+     *
+     * @param u Initial velocity (m/s).
+     * @param a Constant acceleration (m/s^2).
+     * @param t Time elapsed (s).
+     * @return The final velocity (m/s).
+     */
+
+    public static double calculateFinalVelocity(double u, double a, double t) {
+        return u + a * t;
+    }
+
+    /**
+     * Calculates the displacement (s) of an object.
+     * Formula: s = ut + 0.5 * a * t^2
+     *
+     * @param u Initial velocity (m/s).
+     * @param a Constant acceleration (m/s^2).
+     * @param t Time elapsed (s).
+     * @return The displacement (m).
+     */
+
+    public static double calculateDisplacement(double u, double a, double t) {
+        return u * t + 0.5 * a * t * t;
+    }
+
+    /**
+     * Calculates the displacement (s) of an object.
+     * Formula: v^2 = u^2 + 2 * a * s
+     *
+     * @param u Initial velocity (m/s).
+     * @param a Constant acceleration (m/s^2).
+     * @param s Displacement (m).
+     * @return The final velocity squared (m/s)^2.
+     */
+
+    public static double calculateFinalVelocitySquared(double u, double a, double s) {
+        return u * u + 2 * a * s;
+    }
+
+    /**
+     * Calculates the displacement (s) using the average velocity.
+     * Formula: s = (u + v) / 2 * t
+     *
+     * @param u Initial velocity (m/s).
+     * @param v Final velocity (m/s).
+     * @param t Time elapsed (s).
+     * @return The displacement (m).
+     */
+
+    public static double calculateDisplacementFromVelocities(double u, double v, double t) {
+        double velocitySum = u + v;
+        return velocitySum / 2 * t;
+    }
+}

src/test/java/com/thealgorithms/physics/KinematicsTest.java

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+package com.thealgorithms.physics;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+
+/**
+ * Unit tests for the Kinematics utility class.
+ */
+
+public final class KinematicsTest {
+    // A small tolerance for comparing floating-point numbers
+    private static final double DELTA = 1e-9;
+    @Test
+    @DisplayName("Test final velocity: v = u + at")
+    void testCalculateFinalVelocity() {
+        assertEquals(20.0, Kinematics.calculateFinalVelocity(10.0, 2.0, 5.0), DELTA);
+    }
+
+    @Test
+    @DisplayName("Test displacement: s = ut + 0.5at^2")
+    void testCalculateDisplacement() {
+        assertEquals(75.0, Kinematics.calculateDisplacement(10.0, 2.0, 5.0), DELTA);
+    }
+
+    @Test
+    @DisplayName("Test final velocity squared: v^2 = u^2 + 2as")
+    void testCalculateFinalVelocitySquared() {
+        assertEquals(400.0, Kinematics.calculateFinalVelocitySquared(10.0, 2.0, 75.0), DELTA);
+    }
+
+    @Test
+    @DisplayName("Test displacement from average velocity: s = (u+v)/2 * t")
+    void testCalculateDisplacementFromVelocities() {
+        assertEquals(75.0, Kinematics.calculateDisplacementFromVelocities(10.0, 20.0, 5.0), DELTA);
+    }
+
+    @Test
+    @DisplayName("Test with negative acceleration (deceleration)")
+    void testDeceleration() {
+        assertEquals(10.0, Kinematics.calculateFinalVelocity(30.0, -4.0, 5.0), DELTA);
+        assertEquals(100.0, Kinematics.calculateDisplacement(30.0, -4.0, 5.0), DELTA);
+
+        assertEquals(100.0, Kinematics.calculateFinalVelocitySquared(30.0, -4.0, 100.0), DELTA);
+        assertEquals(100.0, Kinematics.calculateDisplacementFromVelocities(30.0, 10.0, 5.0), DELTA);
+    }
+}